<PAGE>

                                                                    Exhibit 10.8


                               SUBLEASE AGREEMENT
                               ------------------

     THIS SUBLEASE AGREEMENT ("Sublease") is made and entered into effective as
                               --------
of the 22nd day of March, 2002 (the "Effective Date"), by and between SWS
                                     --------------
SECURITIES, INC., a Texas corporation formerly known as Southwest Securities,
Inc. ("Sublessor"), and CITADEL SECURITY SOFTWARE, INC., a          corporation
       ---------                                           --------
("Sublessee").
  ---------

                              W I T N E S S E T H:
                              - - - - - - - - - -

     WHEREAS, Northpark Central - VEFII, L.P., as successor-in-interest to
Connecticut General Life Insurance Company ("Landlord"), as landlord, and
                                             --------
Sublessor, as tenant, have made and entered into that certain Office Lease
Agreement dated as of October 3, 1994, as amended by those two certain
amendments dated May 12, 1995 and          , 1997 respectively (said Lease
                                  ---------
Agreement, together with all amendments thereto, if any, being hereinafter
referred to as the "Primary Lease"), which Primary Lease provides for the lease
                    -------------
and demise by Landlord to Sublessor of those certain premises more particularly
described in the Primary Lease, but which are generally described as consisting
of Suite 100 (the "Primary Lease Premises") in the office building commonly
                   ----------------------
known and referred to as Northpark Central, located at 8750 N. Central
Expressway in Dallas, Dallas County, Texas (the "Building"); and
                                                 --------

     WHEREAS, a true and correct copy of the Primary Lease is attached hereto as
Exhibit "A" and made a part hereof for all purposes; and

     WHEREAS, Sublessor desires to sublease to Sublessee the below-described
portion of the Primary Lease Premises, and Sublessee desires to accept and
sublease the same, all upon and subject to the terms and conditions set forth
hereinbelow.

     NOW, THEREFORE, for and in consideration of the above and foregoing
premises and in consideration of the mutual terms, conditions, covenants and
agreements herein contained, and for other good and valuable consideration, the
receipt and sufficiency of which consideration is hereby acknowledged by each of
the parties hereto, Sublessor and Sublessee do hereby agree as follows:

     1. Demise and Description of Property. Sublessor hereby subleases to
        ----------------------------------
Sublessee, and Sublessee hereby subleases from Sublessor, upon and subject to
the terms, limitations and conditions set forth herein and in the Primary Lease,
the Primary Lease Premises (hereinafter referred to as the "Premises"), which
                                                            --------
Premises is more particularly described on Exhibit "B" attached hereto and made
                                           ----------
a part hereof for all purposes. Notwithstanding anything contained herein to the
contrary, Sublessee shall have the right to occupy the entire Premises beginning
on the Sublease Commencement Date; provided, however, that commencing on such
                                   --------  -------
Sublease Commencement Date through and including May 31, 2003, Sublessee shall
only be obligated to pay Sublease Rent (as hereinafter defined) on 7,305
rentable square feet (the "Initial Stage") of the Premises. Commencing on June
                           -------------
1, 2003, and continuing until the Expiration Date, Sublessee shall be obligated
to pay Sublease Rent on the Initial Stage and the remaining 6,431 rentable
square feet (the "Second Stage") of the Premises as more fully set forth in
                  ------------
Paragraph 3 hereof.
-----------

     2. Term; Surrender.

          A. Term. The term ("Term") of this Sublease is (3) years. The Term
             ----             ----
shall commence on the earlier to occur of (a) the date on which Sublessee opens
for conduct of business in the Premises, or (b) 6:00 p.m. on March 22, 2002 (the
first to occur of such dates being hereinafter referred to as the "Sublease
                                                                   --------
Commencement Date"). The Term shall end at 11:59 p.m. (Dallas, Texas time) on
-----------------
February 28, 2005 (the "Expiration Date"), or at such earlier date as this
                        ---------------
Sublease may be terminated pursuant to the terms of this Sublease; provided,
however, this Sublease shall automatically terminate upon the expiration or
termination for any reason of the Primary Lease.

          B. End of Term. Upon the expiration or termination of this Sublease,
             -----------
Sublessee must: (i) surrender to Sublessor any keys, electronic ID cards, and
other access devices to the Premises at the place

<PAGE>

then fixed hereunder for payment of rent and other charges hereunder to
Sublessor; (ii) remove all of Sublessee's trade fixtures and other personal
property from the Premises; (iii) surrender the Premises in "broom clean"
condition and in compliance with the terms and conditions of the Primary Lease
pertaining to surrender of the Premises, other than any failure to comply that
is caused by actions of or omissions of required actions of Sublessor; (iv)
except for reasonable wear and tear resulting from the uses permitted hereunder
and under the Primary Lease, surrender the Premises and fixtures in the same
condition in which Sublessee received them, subject to approved alterations in
accordance with Exhibit C attached hereto; and (v) deliver the Premises to
                ---------
Sublessor free and clear of any and all hazardous materials and substances so
that the condition of the Premises conforms at such time with all applicable
environmental laws, ordinances, rules and regulations to the extent such
hazardous materials or substances were placed in or transferred to the Premises
on or after the Effective Date (other than by Sublessor, Landlord or any other
tenant of the Building).

     3. Sublease Rent. For the Term of this Sublease, Sublessee shall pay to
        -------------
Sublessor as base rent (the "Sublease Rent") for the Premises as follows:
                             -------------

<TABLE>
<CAPTION>
-------------------------------------------------------------------------------------------------------------
          Period              Rate Per Square Foot      Annual Sublease Rent         Monthly Sublease Rent
          ------              --------------------      --------------------         ---------------------
-------------------------------------------------------------------------------------------------------------
<S>                          <C>                      <C>                           <C>
Sublease Commencement Date   $16.00 (Initial Stage    $116,880.00                   $9,740.00
- May 31, 2003               only)
-------------------------------------------------------------------------------------------------------------
June 1, 2003 - February      $16.00 (Initial Stage)   $116,880.00 (Initial Stage)   $9,740.00 (Initial Stage)
28, 2005                     $14.00 (Second Stage)    $90,034.00 (Second Stage)     $7,502.83 (Second Stage)
                                                      $206,914.00 (Total)           $17,242.83 (Total)
----------------------------- ------------------------------------------------------ ------------------------
</TABLE>

Subject to the immediately preceding sentence, the Sublease Rent shall be paid
in advance at least five (5) days prior to the first day of each calendar month
during the Term. Notwithstanding anything to the contrary set forth herein,
Sublessor hereby agrees to abate all Sublease Rent and Additional Rent (as
defined below) payments for the term (the "Abatement Period") commencing March
                                           ----------------
22, 2002 through and including April 30, 2002. The Sublease Rent shall be paid
to Sublessor at Sublessor's address as provided on the signature page of this
Sublease or to such other person or at such other address as Sublessor may from
time to time designate in writing. Sublessor may, at its option, bill Sublessee
for Sublease Rent, but no delay or failure by Sublessor in providing such a bill
shall relieve Sublessee from the obligation to pay the Sublease Rent on the
first day of each month as provided herein. All payments shall be in the form of
a check unless otherwise agreed by Sublessor, provided that payment by check
shall not be deemed made if the check is not duly honored with good funds;
provided, further, that if any such check is ever returned for lack of
sufficient funds or is otherwise not duly honored with good funds, then
Sublessor may thereafter require, upon written notice thereof to Sublessee, that
all future payments of Rent or other charges under this Sublease be made in cash
or cash equivalent mode. Commencing upon the expiration of the Abatement Period,
in addition to the Rent and any other sums or amounts required to be paid by
Sublessee to Sublessor pursuant to this Sublease, Sublessee shall also pay to
Sublessor, concurrently with the payments of said Rent or other charges, the
amount of any applicable sales, use or excise tax, rent tax or other tax with
respect thereto (other than any general income tax payable by Sublessor with
respect thereto) as the same may be levied, imposed or assessed by any federal,
state, county or municipal government entity or agency. If the Term of this
Sublease commences or ends at any time other than the first day of a calendar
year, then Sublease Rent shall be prorated for such year according to the number
of days of the Term in such year.

     4. Operating Expenses, Real Estate Taxes and Additional Pass Through Costs.

          A. Definitions. The following terms as used in this Sublease will have
             -----------
the meaning following respective meanings:

               (i) The term "Operating Expenses" as used in this Sublease has
                             ------------------
the same meaning as the same term set forth in Section 2.201(b) of the Primary
Lease.

               (ii) The term "Real Estate Taxes" as used in this Sublease has
                              -----------------
the same meaning as the same term set forth in Section 2.201(c) of the Primary
Lease.

                                      -2-

<PAGE>

               (iii) The term "Additional Pass Through Costs" as used in this
                               -----------------------------
Sublease has the same meaning as set the same term set forth in Section 2.201(d)
of the Primary Lease.

               (iv) The term "Excess Operating Expenses" means the amount by
                              -------------------------
which the Operating Expenses for the Building for a given calendar year exceed
the Operating Expenses for the Building for the calendar year 2002.

               (v) The term "Excess Real Estate Taxes" means the amount by which
                             ------------------------
the Real Estate Taxes for the Building for a given calendar year exceed the Real
Estate Taxes for the Building for the calendar year 2002.

               (vi) The term "Sublessee's Share" means a percentage determined
                              -----------------
by dividing the size of the Premises then occupied by Sublessee by 491,803
(which the parties agree is the deemed Rentable Square Feet of the Building
regardless of what any subsequent re-measurement might reveal). Therefore,
Sublessee's Share equals 2.79% (i.e. 13,736 / 491,803 = .0279).

               (vii) The term "Controllable Operating Expenses" means Operating
                               -------------------------------
Expenses other than insurance premiums and utilities.

          B. Payment of Excess Operating Expenses and Excess Real Estate Taxes.
             -----------------------------------------------------------------
If there are Excess Operating Expenses and/or Excess Real Estate Taxes for any
calendar year subsequent to 2002, Sublessee must pay to Sublessor as Additional
Rent Sublessee's Share of the Excess Operating Expenses and the Excess Real
Estate Taxes.

          C. Estimated Payments. Sublessor will deliver to Sublessee Sublessor's
             ------------------
reasonable estimate of the Excess Operating Expenses and the Excess Real Estate
Taxes for the next calendar year (which estimate will be based upon Landlord's
similar estimate to be provided to Sublessor pursuant to Section 2.203 of the
Primary Lease). Sublessee must pay to Sublessor monthly, with the Sublease Rent,
an amount equal to 1/12th of Sublessee's Share of the estimated Excess Operating
Expenses and the estimated Excess Real Estate Taxes for the applicable calendar
year. Sublessor may adjust its estimate by delivering 30 days prior written
notice to Sublessee at any time during the applicable calendar year if actual
Excess Operating Expenses and/or Excess Real Estate Taxes are substantially
different from the estimate, and thereafter payments by Sublessee under this
paragraph will adjust accordingly. The term "calendar year" includes partial
calendar years.

          D. Reconciliation of Operating Expenses and Real Estate Taxes. No
             ----------------------------------------------------------
later than one hundred twenty (120) days after the end of (i) each calendar year
and (ii) the expiration of the Term, Sublessor will deliver to Sublessee a
statement setting out in reasonable detail the actual Excess Operating Expenses
and the actual Excess Real Estate Taxes for the prior calendar year. Sublessee
acknowledges that such statement will by necessity rely upon the statement
received from Landlord pursuant to Section 2.203 of the Primary Lease. If the
estimated payments made by Sublessee during the prior calendar year exceed
Sublessee's share of actual Excess Operating Expenses and actual Excess Real
Estate Taxes for that year, Sublessor will credit the difference against the
next ensuing installments of Rent due from Sublessee under this Sublease. If
estimated payments made by Sublessee during the prior calendar year under this
paragraph are less than Sublessee's Share of the actual Excess Operating
Expenses and actual Excess Real Estate Taxes for that year, Sublessee must pay
the amount of the difference to Sublessor in cash within thirty (30) days after
delivery of any invoice therefor by Sublessor accompanied by a copy of
Landlord's statement of the actual Excess Operating Expenses and Excess Real
Estate Taxes for that year as additional Rent that Landlord has previously
delivered to Sublessor pursuant to Section 2.203 of the Primary Lease.

     5. Additional Rent. In addition to the Sublease Rent provided in Paragraph
        ---------------                                               ---------
3 hereof, Sublessee shall also reimburse to Sublessor all such other sums of
-
money becoming due and payable by Sublessor to Landlord under the Primary Lease
and relating to the Premises ("Additional Rent"), including but not limited to
                               ---------------
the Sublessee's Share of Excess Operating Expenses, Excess Real Estate Taxes and
the Additional Pass Through Costs. Sublease Rent and all Additional Rent are
sometimes collectively referred to in this Sublease as "Rent." All Rent shall be
                                                        ----
paid without notice, demand, abatement, deduction or setoff, except as otherwise
expressly provided in this Sublease.

                                      -3-

<PAGE>

     6. Prepaid Rent. Contemporaneously with the delivery by Sublessee to
        ------------
Sublessor of this Sublease, Sublessee shall deliver to Sublessor the amount of
Twenty Six Thousand Nine Hundred Eighty Two and 83/100 Dollars ($26,982.83) (the
"Prepaid Rent "), which amount reflects the first month's rent of $9,740.00 (to
 ------------
be applied against the rent due for the month of May, 2002) and the last month's
rent of $17,242.83 (to be applied against the rent due for the month of
February, 2005). The Prepaid Rent shall be held by Sublessor, without liability
for interest, as security for the performance by Sublessee of Sublessee's
covenants and obligations under this Sublease, it being expressly understood
that the Prepaid Rent shall not be considered a measure of Sublessee's liability
for damages in the event of a default by Sublessee. If Sublessor transfers its
interest in the Lease, Sublessor will within thirty (30) days of such transfer,
at Sublessor's option, either (i) assign any Prepaid Rent not already applied to
Rent to the transferee and upon assumption by such transferee of liability for
the Prepaid Rent, Sublessor shall have no further liability for the application
of such Prepaid Rent, or (ii) return the Prepaid Rent to Sublessee.

     7. Acceptance and Use of the Premises.

          A. Acceptance of Premises. Subject to the terms of Exhibit C hereto,
             ----------------------                          ---------
Sublessee accepts the Premises in its present, "AS-IS, WHERE IS" condition and
with all faults. By occupying the Premises, Sublessee: (a) acknowledges that
Sublessee has had full opportunity to examine the Premises and is fully
informed, independently of Sublessor or any employee, agent, representative,
shareholder, officer or director of Sublessor, as to the character, construction
and structure of the Premises; (b) acknowledges that neither Sublessor nor any
of Sublessor's employees, agents, representatives, shareholders, officers or
directors, has made any representations, warranties or promises with respect to
the Premises, including without limitation any representation or warranty as to
fitness thereof for any purpose; (c) accepts the Premises in an "AS-IS, WHERE
IS" condition and acknowledges that the Premises comply with all requirements
imposed upon Sublessor under this Sublease; and (d) acknowledges and agrees that
the Premises are subject to the limitations, encumbrances, and other matters
described in the Primary Lease. TO THE EXTENT ALLOWED BY LAW, SUBLESSEE HEREBY
WAIVES ANY AND ALL RIGHTS AND PROTECTIONS WHICH MIGHT OTHERWISE BE AFFORDED
SUBLESSEE AT LAW OR OTHERWISE CONCERNING HABITABILITY OR SUITABILITY OF THE
PREMISES OR THE CONDITION OF THE PREMISES (INCLUDING ANY BUILDINGS OR
IMPROVEMENTS) AS OF THE DATE HEREOF. Notwithstanding the foregoing, Sublessee
shall not be responsible for any default by Sublessor under the Primary Lease,
except to the extent the subject matter of any such default constitutes an
obligation of Sublessee hereunder or under the Primary Lease.

          B. Maintenance of Premises. Sublessee shall maintain the Premises in
             -----------------------
good condition and repair and in all respects in compliance with all obligations
of Sublessor as tenant under the Primary Lease.

          C. Use of Premises. The Premises shall be used by Sublessee only for
             ---------------
the uses and purposes permitted under the Primary Lease and for no other use or
purpose.

          D. Ownership of Improvements. Sublessee hereby acknowledges and agrees
             -------------------------
that Sublessor shall be and remain the owner of all improvements constructed
upon the Premises, as the same may be altered, expanded and/or improved from
time to time, during the term of this Sublease and thereafter (subject only to
the terms of the Primary Lease). Sublessor shall retain and have all rights to
depreciation deductions and tax credits arising from Sublessor's ownership of
the Improvements. Upon expiration or earlier termination of this Sublease,
Sublessee shall have no further rights with respect to the improvements or
interest therein.

          E. Signage. Subject to the prior approval of the Landlord and to the
             -------
terms and provisions of the Primary Lease, Sublessee shall have the right, at
Sublessee's sole cost and expense, to install signage identifying Sublessee in
the reception area of the Premises in accordance with the applicable building
rules and regulations.

          F. Intentionally Deleted.
             ---------------------

     8. Additional Agreements and Covenants.

          A. Obligations Under Primary Lease. Sublessee hereby assumes and
             -------------------------------
agrees to perform all obligations of Sublessor as tenant under the Primary Lease
relating to the Premises, and Sublessee agrees to abide by

                                      -4-

<PAGE>

and comply with all of the provisions of the Primary Lease during the term of
this Sublease, except that: (i) the payment of rent and other charges by
Sublessee shall be supplemented and modified by the provisions of Paragraphs 3,
                                                                  --------------
4 and 5 of this Sublease; (ii) Sublessee shall have no option to renew or extend
-------
the term hereof (notwithstanding the availability of any renewal or extension
options under the Primary Lease), and (iii) the following provisions of the
Primary Lease shall not be applicable to Sublessee: Sections 1.2, 2.1, 2.2,
6.301, 11, 15.202, Exhibits D, E and F, and Riders 1-6. Sublessee hereby
acknowledges that Sublessee has read and is familiar with the terms and
conditions of the Primary Lease, and Sublessee further hereby acknowledges and
agrees that (a) this Sublease is and shall be and remain expressly subject to
all of the terms and conditions of the Primary Lease, and (b) except as
otherwise specifically set forth in this Sublease, Sublessor expressly retains
and reserves all rights and benefits applicable to Sublessor as tenant under the
Primary Lease.

          B. Incorporation of Primary Lease. Except as specifically excluded
             ------------------------------
from application to Sublessee pursuant to Paragraph 8(A) hereinabove, the
                                          --------------
provisions of the Primary Lease, to the extent that they do not conflict with
specific provisions contained in this Sublease, are fully incorporated into this
Sublease. In the event of any conflict between the provisions of the Primary
Lease and the provisions contained in this Sublease, the provisions of this
Sublease shall be controlling. Sublessee hereby agrees to be bound to Sublessor
by, and, except as may be specifically excluded from application to Sublessee
pursuant to Paragraph 8A hereinabove, to comply with all of the terms and
            ------------
conditions of, the Primary Lease and to assume toward Sublessor and perform all
of the covenants, obligations and responsibilities that Sublessor by the Primary
Lease assumes toward the Landlord. SUBLESSEE HEREBY AGREES TO INDEMNIFY, DEFEND
(WITH COUNSEL APPROVED IN ADVANCE IN WRITING BY SUBLESSOR) AND HOLD HARMLESS
SUBLESSOR, AND SUBLESSOR'S AGENTS, FROM AND AGAINST ANY AND ALL CLAIMS,
LIABILITY, CAUSES OF ACTION, LOSS, DAMAGES, COSTS AND EXPENSES ARISING FROM (i)
ANY BREACH, VIOLATION OR NON-PERFORMANCE BY SUBLESSEE OF ANY OF THE TERMS AND
PROVISIONS OF THE PRIMARY LEASE OR THIS SUBLEASE, OR ARISING UNDER THE PRIMARY
LEASE, OR RESULTING FROM SUBLESSEE'S USE OR OCCUPANCY OF THE PREMISES, OR (ii)
ANY PERSONAL OR BODILY INJURY TO PERSONS OR DAMAGE TO PROPERTY TO THE EXTENT
THAT SUCH DAMAGE OR INJURY WAS CAUSED, EITHER PROXIMATELY OR REMOTELY, BY ANY
ACT OR OMISSION, WHETHER NEGLIGENT OR NOT, OF SUBLESSEE OR ANY OF SUBLESSEE'S
AGENTS, SERVANTS, EMPLOYEES, CONTRACTORS, CUSTOMERS, GUESTS, OR INVITEES OR OF
ANY OTHER PERSON ENTERING ONTO THE PREMISES UNDER OR WITH THE EXPRESS OR IMPLIED
INVITATION OF SUBLESSEE. SUBLESSOR HEREBY AGREES TO INDEMNIFY, DEFEND (WITH
COUNSEL APPROVED IN ADVANCE IN WRITING BY SUBLESSEE) AND HOLD HARMLESS
SUBLESSEE, AND SUBLESSEE'S AGENTS, FROM AND AGAINST ANY AND ALL CLAIMS,
LIABILITY, CAUSES OF ACTION, LOSS, DAMAGES, COSTS AND EXPENSES ARISING FROM (i)
ANY BREACH, VIOLATION OR NON-PERFORMANCE BY SUBLESSOR OF ANY OF THE TERMS AND
PROVISIONS OF THE PRIMARY LEASE (BUT ONLY TO THE EXTENT NOT REQUIRED TO BE
PERFORMED BY SUBLESSEE HEREUNDER) OR THIS SUBLEASE, OR (ii) ANY PERSONAL OR
BODILY INJURY TO PERSONS OR DAMAGE TO PROPERTY TO THE EXTENT THAT SUCH DAMAGE OR
INJURY WAS CAUSED, EITHER PROXIMATELY OR REMOTELY, BY ANY ACT OR OMISSION,
WHETHER NEGLIGENT OR NOT, OF SUBLESSOR OR ANY OF SUBLESSOR'S AGENTS, SERVANTS,
EMPLOYEES, CONTRACTORS, CUSTOMERS, GUESTS, OR INVITEES OR OF ANY OTHER PERSON
ENTERING ONTO THE PREMISES UNDER OR WITH THE EXPRESS OR IMPLIED INVITATION OF
SUBLESSOR. THE INDEMNIFICATION OBLIGATIONS OF SUBLESSOR AND SUBLESSEE PURSUANT
TO THIS SECTION 8(B) SHALL SURVIVE THE EXPIRATION OR EARLIER TERMINATION OF THIS
        ------------
SUBLEASE.

          C. Services and Other Rights. Notwithstanding anything herein
             -------------------------
contained to the contrary, Sublessee hereby acknowledges and agrees that the
only services or other rights that Sublessee is entitled to under this Sublease
are those to which Sublessor is entitled as "Tenant" under the Primary Lease,
and Sublessee shall have all such rights of Sublessor as "Tenant" thereunder,
except to the extent limited or prohibited by the terms of this Sublease or the
terms of the Primary Lease. Sublessee hereby agrees that Sublessee shall look
solely to Landlord under the Primary Lease for all such services and other
rights and that Sublessor shall not be responsible therefor, except to the
extent expressly set forth in this Sublease to the contrary and except to the
extent of any failure of Sublessor to comply with the terms and obligations of
the Primary Lease, including Sublessor's payment obligations thereunder.

                                      -5-

<PAGE>

          D. Exculpation. Sublessee hereby acknowledges and agrees that
             -----------
Sublessor shall not be responsible for any repairs to the Premises, nor shall
Sublessor, nor any of Sublessor's partners, officers, directors, shareholders,
agents, employees or representatives, be liable for any of the following: (i)
any of the Landlord's obligations under the Primary Lease; (ii) any interruption
in utilities or services to the Premises; (iii) any loss of or damage to any
property of Sublessee or of Sublessee's employees, agents, customers, guests or
invitees (whether by theft or otherwise); (iv) the failure of Landlord to
perform any obligation of Landlord under the Primary Lease; or (v) any damage or
disturbance caused by others. Sublessor's partners, officers, directors,
shareholders, employees, agents or representatives will have no personal
liability under this Sublease, it being hereby agreed that the liability of
Sublessor and Sublessor's partners, officers, directors, shareholders, agents,
employees and representatives for any default by Sublessor under the terms of
this Sublease shall be limited to Sublessee's actual direct, but not
consequential, damages therefor.

          E. Default Under Primary Lease. No default of Landlord under the
             ---------------------------
Primary Lease shall affect this Sublease or waive or defer the performance of
any of Sublessee's obligations hereunder (except to the extent the terms of the
Primary Lease expressly waive or defer the performance of Sublessor's
obligations thereunder); provided, however, that in the event of any such
default or failure by Landlord, Sublessor agrees, upon Sublessor's receipt of
written notice thereof from Sublessee, and at Sublessee's expense, to make
demand upon Landlord to perform Landlord's obligations under the Primary Lease
in accordance with the terms of the Primary Lease (but without obligation of
Sublessor to take any other action or incur any expense to enforce Landlord's
obligations under the Primary Lease). Sublessee shall pay all costs and
expenses, including reasonable attorneys' fees, that may be incurred by
Sublessor in enforcing the provisions of this Sublease or in enforcing
Landlord's obligations under the Primary Lease if requested to do so by
Sublessee.

          F. Insurance. Sublessee shall obtain and maintain in force and effect
             ---------
with respect to the Premises, throughout the entire term of this Sublease, any
and all insurance required to be maintained by the "tenant" pursuant to the
terms of the Primary Lease. It is agreed that any and all insurance required to
be maintained by Sublessee pursuant to the terms of the Primary Lease (as
incorporated herein and assumed by Sublessee hereunder) shall: (i) name
Sublessor, each leasehold mortgagee holding a leasehold mortgage on this
Sublease or the Premises or any part thereof, Landlord, and Landlord's property
manager as additional loss payees with respect to all property insurance; (ii)
contain waivers of subrogation applicable to each of Sublessor, each aforesaid
leasehold mortgagee, Landlord and Landlord's property manager; (iii) include a
standard mortgage clause in favor of each aforesaid leasehold mortgagee; (iv)
shall name Sublessor, each aforesaid leasehold mortgagee, Landlord and
Landlord's property manager as additional insureds with respect to liability
insurance; and (v) require at least thirty (30) days' advance written notice to
Sublessor, Landlord, Landlord's property manager and any applicable mortgagee
prior to the cancellation or modification of any such insurance. All insurance
policies required to be maintained by Sublessee hereunder are to be written by
insurance companies reasonably satisfactory to Sublessor and Landlord. True,
correct and complete copies of all such insurance policies (or certificates
thereof in form and content reasonably satisfactory to Sublessor and Landlord),
evidencing that all such insurance policies required to be obtained and
maintained by Sublessee hereunder have been obtained and paid for, shall be
provided to Sublessor, Landlord, Landlord's property manager and any applicable
mortgagees concurrently with the execution of this Sublease and thereafter at
least thirty (30) days prior to the expiration date of any then-existing
policies.

          G. Use of Personal Property. In connection with this Sublease,
             ------------------------
Sublessor hereby agrees that Sublessee shall have the use of the personal
property (the "Personal Property") listed on Exhibit "D" at no charge to
               -----------------             ----------
Sublessee. Upon the expiration of the Term, Sublessee shall return the Personal
Property to Sublessor in the condition existing as of the date hereof, normal
wear and tear excepted. Sublessee hereby acknowledges that Sublessor makes no
representations, warranties or promises with respect to the Personal Property,
including, without limitation, any representation or warranty as to the
condition thereof or the fitness thereof for any purposes, and Sublessor accepts
the Personal Property in its "AS-IS, WHERE-IS" condition.

     9. Intentionally Deleted.
        ---------------------

     10. Assignment and Subletting. Except upon the prior written consent of
         -------------------------
Sublessor and Landlord, which consent may be granted or withheld in the sole
discretion of Landlord as provided under the Primary Lease and/or in the sole
discretion of Sublessor, Sublessee will not voluntarily or involuntarily
transfer, convey, assign,

                                      -6-

<PAGE>

mortgage or pledge this Sublease or any right or interest of Sublessee
hereunder, nor sublet any part of the Premises, nor permit the use or occupancy
of any portion of the Premises by anyone other than Sublessee.

     11. Parking. Provided that, and for so long as, no Event of Default has
         -------
occurred and is continuing under this Sublease, Sublessee shall have a
nonexclusive right to use one (1) parking space for each 333 rentable square
feet of leased space actually occupied by Tenant (such parking spaces to be
located within the Garage) during the Term of this Sublease, with the
understanding that (i) 26.53% of the Sublessee's total parking spaces will be
reserved spaces as and to the extent provided in the Primary Lease, and (ii) in
determining the number of reserved spaces, a fraction will be rounded to the
lower number (i.e., 13.7 spaces will equal 13 spaces). Sublessee will not be
required to pay rent with respect to any unreserved spaces or for the first six
(6) reserved spaces as provided in the Primary Lease. For each reserved space
above six (6), Sublessee will pay monthly rental per space equal to $10.00 as
Additional Rent. All payments of rent for parking spaces shall be made (i) at
the same time as the Sublease Rent is due under this Sublease, and (ii) to
Sublessee or to such persons (for example but without limitation, the manager of
the Garage) as Sublessor may direct from time to time. Sublessee's use of such
parking spaces shall be subject to the terms and conditions of the Primary
Lease.

     12. Brokers. Sublessor and Sublessee agree and represent to one another
         -------
that no finder or broker has been involved in the procurement, negotiation or
execution of this Sublease, except for Cushman & Wakefield of Texas, Inc. and
Julian J. Studley, Inc. ("Broker", whether one or more), and that Broker is the
                          ------
only broker entitled to a fee or commission for the procurement, negotiation or
execution of this Sublease (which Broker's commission shall be paid by Sublessor
pursuant to a separate commission agreement). SUBLESSOR AND SUBLESSEE HEREBY
AGREE TO DEFEND, INDEMNIFY AND HOLD EACH OTHER HARMLESS AGAINST ANY LOSS, CLAIM,
EXPENSE OR LIABILITY WITH RESPECT TO ANY COMMISSIONS OR BROKERAGE FEES (EXCEPT
AS OTHERWISE SET FORTH IN THE IMMEDIATELY PRECEDING SENTENCE) CLAIMED ON ACCOUNT
OF THE EXECUTION AND/OR RENEWAL OF THIS SUBLEASE OR THE EXPANSION OF THE
PREMISES DUE TO ANY ACTION OF THE INDEMNIFYING PARTY. THE OBLIGATIONS OF
INDEMNITY SET FORTH IN THIS PARAGRAPH 12 SHALL SURVIVE THE EXPIRATION OR EARLIER
                            ------------
TERMINATION OF THIS SUBLEASE.

     13. Sublesse Improvements. Sublessor shall be responsible for the
         ---------------------
construction of all improvements (the "Sublease Improvements") to be made to the
                                       ---------------------
Premises in accordance with Exhibit "C" attached hereto and made a part hereof
                            ----------
for all purposes; provided, however, such construction shall be subject to the
terms and conditions of the Primary Lease (including, without limitation,
Section 6.303 of the Primary Lease attached thereto).

     14. Default and Remedies.

          A. Event of Default. The occurrence of any one or more of the
             ----------------
following events shall constitute an event of default ("Event of Default") by
                                                        ----------------
Sublessee under this Sublease:

               (i) the failure of Sublessee to pay any installment of Rent,
Additional Rent or other charge or money obligation due under this Sublease, and
such failure continues for a period of three (3) business days after written
notice thereof to Sublessee (provided that, if two such failures occur in any
consecutive twelve (12) month period, Sublessee shall not be entitled thereafter
to any such notice of, or such period to cure, any subsequent failure, and any
such subsequent failure shall be and constitute an immediate Event of Default
under this Sublease);

               (ii) the failure of Sublessee to perform, comply with or observe
any agreement, covenant or obligation of Sublessee under this Sublease other
than the payment of rent or other monetary amounts, and such failure continues
for a period of fifteen (15) days after written notice thereof to Sublessee;

               (iii) the making by Sublessee of any assignment for the benefit
of Sublessee's creditors;

               (iv) the levying on or against the property of Sublessee of a
writ of execution or attachment that is not released or discharged within thirty
(30) days;

                                      -7-

<PAGE>

               (v) the institution in a court of competent jurisdiction of
bankruptcy proceedings against Sublessee or any of Sublessee's shareholders, or
for the appointment of a receiver of the property of Sublessee, provided that
such proceedings are not dismissed, and any receiver, trustee, or liquidator
appointed therein is not discharged, within thirty (30) days after the
institution of said proceedings;

               (vi) the doing or permitting to be done by Sublessee of any act
which creates a mechanics' lien or claim against the Premises (however, if such
mechanics' lien or claim would not constitute a default or Event of Default
under the Primary Lease if released within thirty (30) days, then such
mechanics' lien or claim will not constitute an Event of Default hereunder if
fully released and satisfied within thirty (30) days of its inception) ; or

               (vii) the occurrence of any default or Event of Default under the
Primary Lease.

          B. Remedies. Upon the occurrence of an Event of Default, Sublessor, in
             --------
addition to any and all other rights and remedies available to Sublessor at law
or in equity and in addition to all other rights or remedies reserved herein,
shall have the option to pursue any one or more of the following remedies
without any notice or demand whatsoever and without releasing Sublessee from any
obligation under this Sublease (except in the case of a termination of the
Sublease):

               (i) Sublessor may enter the Premises without terminating this
Sublease and may perform any covenant or agreement or cure any condition
creating or giving rise to a default or Event of Default under this Sublease or
under the Primary Lease, and Sublessee agrees to pay to Sublessor on demand, as
Additional Rent, the amount expended by Sublessor in performing such covenants
or agreements or satisfying or observing such condition. Sublessor, and
Sublessor's agents, representatives and employees, shall have the right to enter
the Premises in the exercise of such rights and such entry and such performance
shall not terminate this Sublease or constitute an eviction of Sublessee; or

               (ii) At Sublessor's sole option, Sublessor may terminate this
Sublease by written notice thereof to Sublessee or Sublessor may terminate
Sublessee's right of possession to the Premises, without terminating this
Sublease. In either such event, Sublessee shall surrender (in accordance with
the terms and conditions of this Sublease) possession of and vacate the Premises
immediately and shall deliver possession thereof to Sublessor, and Sublessee
hereby grants to Sublessor, to the extent permitted by applicable law, full and
free license to thereupon enter the Premises, in whole or in part, with or
without process of law, to change any and all door locks without notice of from
whom the new key may be obtained, to deny Sublessee access to the Premises and
to expel or remove Sublessee and any other person, firm or corporation who may
be occupying the Premises or any part thereof and remove any and all property
therefrom, using such lawful force as may be necessary. Upon either Sublessor's
termination of this Sublease or termination of Sublessee's right of possession
to the Premises without terminating this Sublease, as provided herein, Sublessor
shall in either such event be entitled to recovery from Sublessee of all damages
to which Sublessor may be entitled hereunder or at law by virtue thereof,
including (without limitation) all costs and losses incurred by Sublessor as a
result of the Event of Default by Sublessee hereunder and any expenses which
Sublessor may incur in effecting compliance with Sublessee's obligations under
this Sublease, all of which sums Sublessee agrees to reimburse to Sublessor on
demand.

          C. No Termination or Waiver. Institution of a forcible detainer action
             ------------------------
to re-enter the Premises shall not be construed to be an election by Sublessor
to terminate this Sublease. Sublessor may collect and receive any Rent due from
Sublessee and the payment thereof shall not constitute a waiver of or affect any
notice or demand given, suit instituted, or judgment obtained by Sublessor, or
be held or deemed to waive or alter the rights or remedies which Sublessor may
have at law or in equity or by virtue of this Sublease at the time of such
payment.

          D. Remedies Non-exclusive. All rights and remedies of Sublessor
             ----------------------
enumerated in this Sublease shall be cumulative and shall not exclude any other
right or remedy allowed by law. All such rights and remedies may be exercised
and enforced concurrently, whenever and as often as necessary.

     15. Miscellaneous Provisions.

                                      -8-

<PAGE>

          A. Governing Law and Forum. THIS SUBLEASE SHALL BE GOVERNED BY AND
             -----------------------
CONSTRUED UNDER AND IN ACCORDANCE WITH THE LAWS OF THE JURISDICTION IN WHICH THE
PREMISES ARE LOCATED. BY EXECUTING THIS SUBLEASE, EACH PARTY HERETO EXPRESSLY
(a) CONSENTS AND SUBMITS TO PERSONAL JURISDICTION CONSISTENT WITH THE PREVIOUS
SENTENCE, (b) WAIVES TO THE FULLEST EXTENT PERMITTED BY LAW, ANY CLAIM OR
DEFENSE THAT SUCH VENUE IS NOT PROPER OR CONVENIENT AND (c) CONSENTS TO SERVICE
OF PROCESS IN ANY MANNER AUTHORIZED BY TEXAS LAW. ANY FINAL JUDGMENT ENTERED IN
AN ACTION BROUGHT HEREUNDER SHALL BE CONCLUSIVE AND BINDING UPON THE PARTIES
HERETO.

          B. Parties Bound. This Sublease shall be binding on and inure to the
             -------------
benefit of each of the parties hereto and their respective successors and
permitted assigns. Notwithstanding anything to the contrary set forth herein, it
is hereby agreed that Sublessor has the right to assign, transfer, pledge or
otherwise convey any interest of Sublessor in the Premises, the Primary Lease
and/or this Sublease, and Sublessee agrees that in the event of any such
transfer, Sublessor shall automatically be released from all liability under
this Sublease accruing from and after the date of such transfer of interest by
Sublessor, and Sublessee agrees to thereupon look solely to the transferee for
the performance of Sublessor's obligations hereunder accruing from and after the
date of such transfer of interest by Sublessor.

          C. Partial Invalidity. In case any one or more of the provisions
             ------------------
contained in this Sublease shall for any reason be held to be invalid, illegal,
or unenforceable in any respect, such invalidity, illegality, or
unenforceability shall not affect any other provisions hereof and this Sublease
shall be construed as if such invalid, illegal, or unenforceable provisions had
never been included herein.

          D. Prior Agreements Superseded. This Sublease constitutes the sole and
             ---------------------------
entire agreement of the parties with respect to the subject matter hereof and
supersedes any prior understandings or written or oral agreement between the
parties respecting such subject matter.

          E. Disclaimer of Warranty. SUBLESSEE HEREBY EXPRESSLY DISCLAIMS ANY
             ----------------------
IMPLIED WARRANTY THAT THE PREMISES ARE SUITABLE FOR SUBLESSEE'S INTENDED
PURPOSE, AND SUBLESSEE'S OBLIGATION TO PAY RENT AND OTHER CHARGES HEREUNDER IS
NOT DEPENDENT UPON THE CONDITION OF THE PREMISES OR THE PERFORMANCE BY SUBLESSOR
OF ANY OBLIGATIONS HEREUNDER (OTHER THAN SUBLESSOR'S OBLIGATION TO PAY RENT
UNDER THE PRIMARY LEASE). SUBLESSEE SHALL CONTINUE TO PAY THE RENT AND OTHER
CHARGES DUE AND PAYABLE BY SUBLESSEE HEREUNDER WITHOUT ABATEMENT, SET OFF OR
DEDUCTION, NOTWITHSTANDING ANY BREACH OR ALLEGED BREACH BY SUBLESSOR OF
SUBLESSOR'S DUTIES OR OBLIGATIONS HEREUNDER, WHETHER EXPRESS OR IMPLIED.

          F. Attorney's Fees. If any action at law or in equity, including an
             ---------------
action for declaratory relief, is brought by other party hereto to enforce or
interpret the provisions of this Sublease, the prevailing party in such action
shall be entitled to recover from the non-prevailing party such prevailing
party's reasonable attorney's fees and costs incurred, which fees and costs may
be set by the court in the trial of such action or may be enforced in a separate
action for that purpose, and which fees and costs shall be in addition to any
other relief which may be awarded in such action.

          G. Counterparts. To facilitate execution of this Sublease, this
             ------------
Sublease may be executed in one or more counterparts as may be convenient or
required, and an executed copy of this Sublease delivered by facsimile shall
have the effect of an original, executed instrument. All counterparts of this
Sublease shall collectively constitute a single instrument; but, in making proof
of this Sublease, it shall not be necessary to produce or account for more than
one such counterpart. It shall not be necessary for the signature of, or on
behalf of, each party hereto, or that the signature of all persons required to
bind any such party, appear on each counterpart of this Sublease. Each signature
page to any counterpart of this Sublease may be detached from such counterpart
without impairing the legal effect of the signatures thereon and thereafter
attached to another counterpart of this Sublease identical thereto except having
attached to it additional signature pages.

                                      -9-

<PAGE>

          H. No Offer. The submission of this Sublease to Sublessee shall not be
             --------
construed as an offer, nor shall Sublessee have any rights hereunder or to the
Premises, unless and until Sublessor shall have executed a copy of this Sublease
and delivered the same to Sublessee.

          I. Time of Essence. Time is of the essence in this Sublease.
             ---------------

          J. Survival of Sublessee Obligations. Sublessee's obligations under
             ---------------------------------
this Sublease (including, without limitation, each indemnity agreement and hold
harmless agreement of Sublessee contained herein) shall survive the expiration
or earlier termination of this Sublease.

          K. Only Sublessor/Sublessee Relationship. Nothing contained in this
             -------------------------------------
Sublease shall be deemed or construed by the parties hereto or by any third
party to create the relationship of principal and agent, partnership, joint
venture or any association between Sublessor and Sublessee, it being expressly
understood and agreed that nothing contained in this Sublease shall be deemed to
create any relationship between Sublessor and Sublessee other than the
relationship of sublessor and sublessee.

          L. Headings; Miscellaneous. The captions and/or headings of the
             -----------------------
several articles, paragraphs and sections contained herein are for convenience
only and do not define, limit or construe the contents of such articles,
paragraphs or sections. Any reference herein to an article, paragraph or section
shall mean and refer to an article, paragraph or section of this Sublease unless
otherwise expressly specified herein. This Sublease may not be amended or
modified by any act or conduct of the parties or by oral agreements unless
reduced and agreed to in writing signed by both Sublessor and Sublessee. No
waiver of any of the terms of this Sublease shall be binding upon Sublessor
unless reduced to writing and signed by Sublessor. Neither Sublessor's failure
to enforce or require strict performance of any provision of this Sublease, nor
Sublessor's acceptance of Rent or other charges with knowledge of a breach,
default or Event of Default hereunder, shall be a waiver of such breach, default
or Event of Default or any future breach, default or Event of Default hereunder.

          M. Notices. Any notice under this Sublease must be in writing, and
             -------
shall be given or served by (i) personal delivery via a recognized independent
courier service (providing reasonable proof of such delivery), (ii) depositing
the same in the United States mail, postage prepaid, certified mail, return
receipt requested, in either such event addressed to the party to be notified at
the address stated in this Sublease hereinbelow or such other address in the
continental United States of which notice has been given to the other party in
the manner provided herein, or (iii) via facsimile to the respective fax numbers
of the parties hereto as set forth hereinbelow, with either electronic or
telephonic verification of receipt, so long as the original of the facsimile
notice is deposited in the United States mail within three (3) days thereafter.
Notice by personal delivery or via courier shall be effective upon receipt,
notice by mail shall be effective upon deposit in the United States mail in the
manner described above and notice by facsimile shall be effective upon
electronic or telephonic verification of receipt.

          N. Interpretation. When used herein, the singular includes the plural
             --------------
and the plural the singular, and words importing any gender include the other
gender. The terms and conditions of this Sublease represent the result of
negotiations between Sublessor and Sublessee, each of which were represented
and/or had the opportunity to be represented by independent counsel and neither
of which has acted under compulsion or duress; consequently, the normal rule of
construction that any ambiguity be resolved against the drafting party shall not
apply to the interpretation of this Sublease or of any exhibits, addenda or
amendments hereto.

          O. Exhibits. All exhibits attached to this Sublease are deemed to be
             --------
incorporated in this Sublease as if fully set forth hereinabove.

          P. Holidays. In the event that the date upon which any of the duties
             --------
or obligations hereunder to be performed shall occur upon a Saturday, Sunday or
legal holiday, then, in such event, and provided that performance of such
obligation is not earlier required under the Primary Lease, the due date for
performance of any duty or obligation shall thereupon be automatically extended
to the next succeeding business day.

                                      -10-

<PAGE>

          Q. Authority. The individual executing this Sublease on behalf of
             ---------
Sublessee represents and warrants to Sublessor that Sublessee has full right and
authority to enter into this Sublease and performance obligations hereunder.

          R. Entry by Sublessor. Sublessor and its representatives shall have
             ------------------
the right, at all reasonable times, to enter upon the Premises for the purpose
of examining and inspecting the same; provided, however, this section shall not
be construed as imposing any obligation upon Sublessor to inspect the Premises.

          S. Waiver of Jury Trial. IT IS AGREED BY AND BETWEEN SUBLESSOR AND
             --------------------
SUBLESSEE THAT THE RESPECTIVE PARTIES HERETO SHALL AND THEY HEREBY DO, TO THE
EXTENT PERMITTED BY APPLICABLE LAW, WAIVE TRIAL BY JURY IN ANY ACTION,
PROCEEDING OR COUNTERCLAIM BROUGHT BY EITHER OF THE PARTIES HERETO AGAINST THE
OTHER ON ANY MATTERS ARISING OUT OF OR IN ANY WAY CONNECTED WITH THIS SUBLEASE,
THE RELATIONSHIP OF SUBLESSOR AND SUBLESSEE, OR SUBLESSEE'S USE OR OCCUPANCY OF
THE PREMISES. SUBLESSEE FURTHER AGREES THAT, TO THE EXTENT PERMITTED BY
APPLICABLE LAW, SUBLESSEE SHALL NOT IMPOSE ANY COUNTERCLAIM IN A SUMMARY
PROCEEDING OR IN ANY ACTION BASED ON NON-PAYMENT OF RENT OR ANY OTHER PAYMENT
REQUIRED BY SUBLESSEE HEREUNDER.

          T. Defined Terms. Unless otherwise specifically defined in this
             -------------
Sublease, capitalized terms utilized in this Sublease shall have the meaning
ascribed to such terms in the Primary Lease.

          U. Sublessor's Contractual Security Interest and Lien. Sublessor shall
             --------------------------------------------------
have a lien upon, and Sublessee hereby grants to Sublessor a security interest
in, all personal property, furniture and equipment of Sublessee located in the
Premises, as security for the payment of all Rent and the performance of all
other obligations of Sublessee required by this Sublease. At any time after an
Event of Default by Sublessee occurs hereunder, Sublessor may seize and take
possession of any and all such personal property and equipment in accordance
with applicable law, and Sublessor shall have the right, after twenty (20) days'
written notice to Sublessee, to sell such personal property and equipment so
seized at public or private sale and upon such terms and conditions as to
Sublessor may appear advantageous. After the payment of all charges incident to
such sale, the proceeds of such sale shall be applied to the payment of any and
all amounts due to Sublessor pursuant to this Sublease. In the event there shall
be any surplus remaining after the payment of all amounts due to Sublessor, such
surplus shall be held by Sublessor and applied in payment of future Rent as it
becomes due and any surplus remaining after payment of all such Rent shall be
paid over to Sublessee. In its exercise of rights pursuant to this paragraph,
Sublessor shall have all of the rights and remedies of a secured party under the
Uniform Commercial Code or other equivalent and applicable laws of the
jurisdiction in which the Premises are located which relate to the grant and
perfection of security interests of the nature granted pursuant to this
paragraph, and, upon request by Sublessor, Sublessee shall execute and deliver
to Sublessor a financing statement or equivalent or similar applicable
instrument in form sufficient under applicable law to perfect the security
interest of Sublessor in the aforementioned personal property, furniture and
equipment and all proceeds thereof. A photographic reproduction of this Sublease
shall be sufficient as a financing statement, but shall be filed as such only in
the event Sublessee fails to execute and deliver a financing statement requested
by Sublessor hereunder within five (5) business days of such request.

          V. Guaranty. The obligations of Sublessee under this Sublease shall be
             --------
guaranteed by Steven Solomon ("Guarantor") pursuant to the terms of that certain
                               ---------
Guaranty Agreement (the "Guaranty") in the form attached hereto as Exhibit "E"
                         --------                                  ----------
and made a part hereof for all purposes, which Guaranty shall be executed by
Guarantor concurrently with the execution of this Lease.

          W. Landlord's Consent. Sublessor and Sublessee each hereby agree that,
             ------------------
pursuant to the Primary Lease, Landlord must consent to this Sublease and the
terms of this Sublease. Accordingly, as a condition precedent to the
effectiveness of this Sublease, Landlord must execute and deliver to Sublessor
within thirty (30) days after the Effective Date of this Lease a Landlord's
Consent to Sublease in form and substance substantially similar to that set
forth on Exhibit "F" attached hereto and made a part hereof for all purposes. In
         ----------
the event Sublessor fails to obtain the Landlord's Consent to Sublease within
such thirty (30) day period, this Sublease shall terminate and shall be of no
further force or effect, in which event neither party shall have any further
rights or obligations hereunder, except as is otherwise provided hereunder
(including, for example, but without limitation, the

                                      -11-

<PAGE>

survival, notwithstanding such termination, of any indemnity obligations which
by the express terms of this Sublease survive the expiration or termination
hereof).

         [THE REMAINDER OF THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK.]

                                      -12-

<PAGE>

     IN WITNESS WHEREOF, the parties hereto have caused this Sublease to be
executed by their respective duly authorized representatives, effective as of
the date first hereinabove written.

                        SUBLESSOR:
                        ---------

                        SWS SECURITIES, INC.,
                        a Texas corporation
                        formerly known as Southwest Securities, Inc.


                        By:
                           -----------------------------------------------------
                              Name:
                                     -------------------------------------------
                              Title:
                                      ------------------------------------------
                              Address:
                                      ------------------------------------------
                              Phone No.:
                                        ----------------------------------------
                              Fax No.:
                                      ------------------------------------------


                        SUBLESSEE:
                        ---------

                        CITADEL SECURITY SOFTWARE, INC.,
                        a            corporation
                          ----------


                        By:
                           -----------------------------------------------------
                              Name:
                                     -------------------------------------------
                              Title:
                                      ------------------------------------------
                              Address:
                                      ------------------------------------------
                              Phone No.:
                                        ----------------------------------------
                              Fax No.:
                                      ------------------------------------------
List of Exhibits:
----------------

Exhibit "A"    =     Copy of Primary Lease
Exhibit "B"    =     Description of Premises
Exhibit "C"    =     Sublease Improvements Agreement
Exhibit "D"    =     Schedule of Personal Property and Price
Exhibit "E"    =     Guaranty Agreement
Exhibit "F"    =     Form of Landlord's Consent to Sublease

                                      -13-

<PAGE>

                                   EXHIBIT "A"

                                  PRIMARY LEASE
                                  -------------

              (A copy of the Primary Lease follows this cover page)

Exhibit "A" - Primary Lease - Cover Page

<PAGE>

                                   EXHIBIT "B"

                             DESCRIPTION OF PREMISES
                             -----------------------

                      (To be completed prior to execution)

Exhibit "B" - Description of Premises - Cover Page

<PAGE>

                                   EXHIBIT "C"

                         SUBLEASE IMPROVEMENTS AGREEMENT
                         -------------------------------

     This Sublease Improvements Agreement (herein so called) describes and
specifies the rights and obligations of Sublessor and Sublessee under the Lease
to which this Exhibit "C" is attached, with respect to the design, construction
              ----------
and payment for the completion of the Sublease Improvements within the Premises.

     1. Definitions. Any capitalized terms not defined in this Sublease
        -----------
Improvements Agreement shall have the meaning set forth in the Sublease.
Additionally, as used in this Sublease Improvements Agreement, the following
terms (when delineated with initial capital letters) shall have the respective
meaning indicated for each, as follows:

          (a) "Change Costs" means any increase in the Cost of the Work
               ------------
attributable to any change in the scope of the Work requested or made necessary
by Sublessee or its representatives, including, without limitation, (1) a
direction by Sublessee to add to, modify or omit any item of Work contained in
the Plans and Specifications, (2) any additional architectural, design or
engineering services, (3) any changes to materials in the process of
fabrication, (4) the cancellation or modification of supply or fabricating
contracts, or (5) the removal or alteration of any Work completed or in process.

          (b) "Construction Allowance" means the sum of $3.00 per square foot,
               ----------------------
multiplied by the Rentable Area of the Premises.

          (c) "Construction Manager" means any third party engaged by Sublessee
               --------------------
to manage or inspect the performance of the Work. The choice of Construction
Manager shall be subject to the prior written approval of Sublessor and the
Landlord under the Primary Lease.

          (d) "Contractor" means the general contractor selected by Sublessor to
               ----------
perform the Work. Sublessor reserves the right to replace the initial Contractor
and/or to engage other contractors if the initial Contractor fails or refuses to
perform the Work to Sublessor's satisfaction.

          (e) "Cost of the Work" means the cost of performing the Work, all
               ----------------
permit fees (including, without limitation, any fee payable to the Texas
Department of Licensing and Regulation [or any successor thereto]).

          (f) "Excess Amount" means the amount by which the Cost of the Work
               -------------
exceeds the Construction Allowance.

          (g) "Plans and Specifications" means the Plans and Specifications
               ------------------------
prepared in accordance with Section 2 of this Sublease Improvements Agreement.
                            ---------

          (h) "Work" means all materials and labor to be added to the existing
               ----
improvements in the Premises, if any, in order to complete the installation of
the Sublease Improvements within the Premises for Sublessee in accordance with
the Plans and Specifications. Sublessee acknowledges and agrees that only
Building standard materials may be utilized in the performance of the Work
unless otherwise approved in writing by Sublessor and the Landlord under the
Primary Lease. The Work shall not include the purchase and installation of any
voice and data cabling, telephone or other communications equipment unless
specifically included on the Plans and Specifications.

     2. Approval of Design Professionals; Plans and Specifications. All design
        ----------------------------------------------------------
professionals engaged by Sublessee, including, without limitation, architects,
engineers and interior designers shall be subject to the prior written approval
of Sublessor and the Landlord under the Primary Lease. If the Plans and
Specifications have not been completed by the Effective Date of the Sublease,
then no later than May 15, 2002, Sublessee and Sublessor shall agree upon the
Plans and Specifications for the Sublease Improvements to the Premises,
including, without

Exhibit "C" - Sublease Improvements Agreement - Page 1

<PAGE>

limitation, the color scheme and the types of materials and finishes that
Sublessee desires to use within the Premises. Following agreement by Sublessor
and Sublessee with respect to such items, Sublessee shall prepare and deliver
construction documents to Sublessor for approval. Sublessor shall approve or
disapprove such construction documents within ten (10) days after receipt
thereof. If Sublessor does not approve such construction documents, Sublessor
shall specifically identify its objections and Sublessee shall revise such
construction documents to address Sublessor's objections and re-submit the same
to Sublessor for approval within five (5) days thereafter. The foregoing process
shall be implemented repeatedly (but Sublessee covenants to submit construction
documents acceptable to Sublessor not later than the date set forth above in
this paragraph) until Sublessor shall have approved Sublessee's construction
documents. Upon approval by Sublessor, such construction documents shall
constitute the "Plans and Specifications" hereunder.
                ------------------------

     3. Compliance with Applicable Laws. Sublessee acknowledges that the
        -------------------------------
approval by Sublessor and the Landlord under the Primary Lease of the Plans and
Specifications does not imply that the Plans and Specifications comply with, and
neither Sublessor nor the Landlord have any responsibility for compliance of the
Plans and Specifications with, applicable federal, state and local statutes,
codes, ordinances and other regulations.

     4. Application of Construction Allowance; Payment of Excess Amount;
        ----------------------------------------------------------------
Reimbursement of Design Allowance. Sublessor shall credit the Construction
---------------------------------
Allowance against the Cost of the Work and the Excess Amount shall be paid by
Sublessee. Sublessor shall, prior to the commencement of the Work, provide
Sublessee with an estimate, prepared by the Contractor, of the Excess Amount. In
such event Sublessee shall, as a condition to the commencement of the Work,
deposit the full amount of the estimated Excess Amount with Sublessor (the
"Construction Deposit"). The Construction Deposit shall be applied by Sublessor
 --------------------
against the Excess Amount of the Cost of the Work. Any excess in the
Construction Deposit shall be refunded to Sublessee within thirty (30) days
following the substantial completion of the Work and any deficiency in the
Construction Deposit shall be paid by Sublessee to Sublessor within thirty (30)
days following written demand by Sublessor. If Sublessor does not require a
Construction Deposit, Sublessor shall provide to Sublessee an invoice for the
Excess Amount following completion of the Work and Sublessee shall pay such sum
to Sublessor within thirty (30) days thereafter after receipt of such invoice.
The Construction Allowance shall not be used for any purpose other than for
payment of the Cost of the Work. No portion of the Construction Allowance shall
be applied against Rent, or for any other purpose.

     5. Change Costs. Sublessee shall at all times pay all Change Costs incurred
        ------------
by Sublessor, which Change Costs shall be paid as a condition precedent to
Sublessor implementing the change in question.

     6. Change Orders. All changes and modifications in the Work from that
        -------------
contemplated in the Plans and Specifications, whether or not such change or
modification gives rise to a Change Cost, must be evidenced by a written change
order (a "Change Order") executed by both Sublessor and Sublessee. In that
          ------------
regard, Sublessee shall submit to Sublessor such information as Sublessor shall
require with respect to any Change Order requested by Sublessee. Sublessor shall
then return to Sublessee either a proposed form of Change Order (which shall
show any increase in the Cost of the Work), to evidence Sublessor's approval
thereof, or a statement disapproving such requested Change Order and stating the
reasons for such disapproval. Sublessee shall execute and return any approved
Change Order to Sublessor as a condition precedent to the implementation of the
change in question.

     7. Failure to Pay. The amounts payable by Sublessee to Sublessor hereunder
        --------------
shall constitute Rent, and Sublessee's failure to make any such payment when due
shall constitute a default under the Sublease, entitling Sublessor, subject to
any applicable notice and/or grace periods provided in the Sublease, to exercise
any or all of its remedies under the Sublease or this Sublease Improvements
Agreement.

          (a) Performance of Work. Following final approval of the Plans and
              -------------------
Specifications, Sublessor shall instruct the Contractor to proceed with the Work
and will diligently pursue such Work to completion.

     8. Punchlist. Prior to the Sublease Commencement Date, Sublessor and
        ---------
Sublessee shall conduct a walk-through of the Premises (the "Inspection") and
                                                             ----------
specify in writing the Punchlist Items which remain to be performed by
Sublessor. Except for the Punchlist Items so identified, and the obligation of
Sublessor to correct defective work pursuant to Section 10 of this Sublease
                                                ----------
Improvements Agreement, all obligations of Sublessor in regard to the Work shall
be deemed to have been satisfied upon satisfactory completion of the Inspection.
Sublessor

Exhibit "C" - Sublease Improvements Agreement - Page 2

<PAGE>

shall have the right to enter the Premises to complete the Punchlist Items, and
non-intrusive entry by Sublessor, its agents, servants, employees or contractors
for such purpose shall not relieve Sublessee of any of its obligations under the
Lease or impose any liability on Sublessor or its agents, servants, employees or
contractors.

     9. Notices. All notices required or contemplated hereunder shall be given
        -------
to the parties in the manner specified for giving notices under the Sublease.

     10. Non-Compliance of Sublease Improvements. If, within ninety (90) days
         ---------------------------------------
after the Inspection, Sublessee shall provide Sublessor written notice that any
of the Sublease Improvements do not comply with the Plans and Specifications in
any material respects (Sublessee agreeing, however, to promptly provide such
written notice upon discovery of non-compliance), Sublessor will correct such
non-compliance at its own expense. Any non-compliance of which Sublessee has not
given Sublessor written notice within such ninety (90) day period is deemed
waived; provided, however, that Sublessee shall have the right to require
Sublessor to correct any "latent defects" in or affecting the Premises (i.e.,
defects not reasonably discoverable pursuant to the Inspection). Notwithstanding
anything contained herein to the contrary, Sublessor is not required to correct
non-compliance with the Plans and Specifications of any non-Building standard
materials incorporated by Sublessee into the Sublease Improvements nor any
workmanship defects with respect to contractors or subcontractors specially
requested by Sublessee and not generally utilized by Sublessor.

     11. Construction Representatives. Sublessor's and Sublessee's
         ----------------------------
representatives for coordination of construction and approval of matters set
forth herein will be as follows, provided that either party may change his
representative upon written notice to the other:

         10.      Sublessor's Representative:


         Name:
                    ---------------------------------

         Phone:
                    ---------------------------------
         Fax:
                    ---------------------------------


         Sublessee's Representative:


         Name:
                    ---------------------------------

         Phone:
                    ---------------------------------
         Fax:
                    ---------------------------------

Exhibit "C" - Sublease Improvements Agreement - Page 3

<PAGE>

                                   EXHIBIT "D"

                          SCHEDULE OF PERSONAL PROPERTY
                          -----------------------------

                      (To be completed prior to execution)

Exhibit "D" - Schedule of Personal Property - Cover Page

<PAGE>

                                   EXHIBIT "E"

                               GUARANTY AGREEMENT
                               ------------------

     In consideration of the making of that certain Sublease Agreement (as same
may be amended from time to time, the "Sublease") dated March     , 2002,
                                       --------               ----
between SWS SECURITIES, INC., a Texas corporation formerly known as Southwest
Securities, Inc. ("Sublessor"), and CITADEL SECURITY SOFTWARE, INC., a
                   ---------
             corporation ("Sublessee") covering certain space in the building
------------               ---------
commonly known as Northpark Central, in Dallas, Dallas County, Texas, and for
the purpose of inducing Sublessor to enter into and make the Sublease, the
undersigned hereby unconditionally guarantees (i) the full and prompt payment of
the Sublease Rent (as defined in the Sublease) and all other sums required to be
paid by Sublessee under the Lease, and (ii) the reimbursement of Sublessor in
the event of a default under this Sublease for any up-front transactional costs
paid by Sublessor, including but not limited to the Allowance (as such term is
defined in the Sublease) and any leasing commissions (individually, a
"Guaranteed Payment", and collectively, the "Guaranteed Payments") and the full
 ------------------                          -------------------
and faithful performance of all terms, conditions, covenants, obligations and
agreements contained in the Sublease on the Sublessee's part to be performed
(individually, a "Guaranteed Obligation", and collectively, the "Guaranteed
                  ---------------------                          ----------
Obligations") and the undersigned further promises to pay all of Sublessor's
-----------
costs and expenses (including reasonable attorneys' fees) incurred in
endeavoring to collect the Guaranteed Payments or to enforce the Guaranteed
Obligations or incurred in enforcing this Guaranty, as well as all damages which
Sublessor may suffer in consequence of any default or breach under the Sublease
or this Guaranty.

     1. Sublessor may at any time and from time to time, without notice to or
consent by the undersigned, take any or all of the following actions without
affecting or impairing the liability and obligations of the undersigned on this
Guaranty:

     a. grant an extension or extensions of time for payment of any Guaranteed
Payment or time for performance of any Guaranteed Obligation;

     b. grant an indulgence or indulgences in the payment of any Guaranteed
Payment or in the performance of any Guaranteed Obligation;

     c. modify or amend the Sublease or any term thereof or any obligation of
Sublessee arising thereunder;

     d. consent to any assignment or assignments, sublease or subleases and
successive assignments or subleases by Sublessee or by Sublessee's successors or
assigns;

     e. consent to an extension or extensions of the term of the Sublease;

     f. accept other guarantees or guarantors; and/or

     g. release any person primarily or secondarily liable hereunder or under
the Sublease or under any other guaranty of the Sublease.

     The liability of the undersigned under this Guaranty shall not be affected
or impaired by any failure or delay by Sublessor in enforcing any Guaranteed
Payment or Guaranteed Obligation or this Guaranty or any security therefor or in
exercising any right or power in respect thereto, or by any compromise, waiver,
settlement, change, subordination, modification or disposition of any Guaranteed
Payment or Guaranteed Obligation or of any security therefor. In order to hold
the undersigned liable hereunder, there shall be no obligation on the part of
Sublessor, at any time, to resort to Sublessee or to any other guaranty or to
any security or other rights and remedies for payment or performance, and
Sublessor shall have the right to enforce this Guaranty irrespective of whether
or not other proceedings or actions are pending or being taken seeking resort to
or realization upon or from any of the foregoing.

Exhibit "E" - Guaranty Agreement - Page 1

<PAGE>

     2. The undersigned waives all diligence in collection or in protection of
any security, presentment, protest, demand, notice of dishonor or default,
notice of acceleration or intent to accelerate, notice of acceptance of this
Guaranty, notice of any extensions granted or other action taken in reliance
hereon and all demands and notices of any kind in connection with this Guaranty
or any Guaranteed Payment or Guaranteed Obligation.

     3. The undersigned hereby acknowledges full and complete notice and
knowledge of all the terms, conditions, covenants, obligations and agreements of
the Sublease.

     4. The payment by the undersigned of any amount pursuant to this Guaranty
shall not in any way entitle the undersigned to any right, title or interest
(whether by subrogation or otherwise) of Sublessee under the Sublease or to any
security being held for any Guaranteed Payment or Guaranteed Obligation.

     5. This Guaranty shall be continuing, absolute and unconditional and shall
remain in full force and effect until all Guaranteed Payments are made, all
Guaranteed Obligations are performed and all obligations of the undersigned
under this Guaranty are fulfilled.

     6. This Guaranty shall also bind the heirs, personal representatives,
successors and assigns of the undersigned and shall inure to the benefit of
Sublessor and Sublessor's successors and assigns.

     7. This Guaranty shall be governed by and construed according to the laws
of the State of Texas and shall be performed in the county identified in the
first paragraph of this Guaranty. The situs for the resolution (including any
judicial proceedings) of any disputes arising under or relating to this Guaranty
shall be the county referenced in the first paragraph of this Guaranty.

     8. If this Guaranty is executed by more than one person, all singular nouns
and verbs herein relating to the undersigned shall include the plural number,
the obligations of the several guarantors shall be joint and several and
Sublessor may enforce this Guaranty against any one or more guarantors without
joinder of any other guarantor (hereunder or otherwise).

     9. Sublessor and the undersigned intend and believe that each provision of
this Guaranty comports with all applicable law. However, if any provision of
this Guaranty is found by a court to be invalid for any reason, the remainder of
this Guaranty shall continue in full force and effect and the invalid provision
shall be construed as if it were not contained herein.

         [THE REMAINDER OF THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK.]

Exhibit "E" - Guaranty Agreement - Page 2

<PAGE>

     IN WITNESS WHEREOF, the undersigned has executed and delivered this
Guaranty this       day of              , 2002.
              -----        -------------

                                       GUARANTOR:
                                       ---------


                                       -----------------------------------------
                                       STEVE SOLOMON
Address:

---------------------------

---------------------------

Exhibit "E" - Guaranty Agreement - Page 3

<PAGE>

                                   EXHIBIT "F"
                     Form of LANDLORD'S CONSENT TO SUBLEASE

                            March             , 2002
                                  ------------

Northpark Central - VEFII, L.P.
8750 North Central Expressway
Suite 650
Dallas, Texas 75231

               Re:  Office Lease Agreement (as amended from time to time, the
                    "Lease") dated October 3, 1994 by and between Connecticut
                    General Life Insurance Company, predecessor-in-interest to
                    Northpark Central - VEFII, L.P. ("Landlord"), as landlord,
                    and SWS Securities, Inc., formerly known as Southwest
                    Securities, Inc ("Tenant"), as tenant, covering
                    approximately 13,736 rentable square feet (the "Premises")
                    in the improvements commonly known as Northpark Central,
                    Dallas, Texas.

Gentlemen:

     The undersigned hereby advise Landlord that Tenant desires to sublease
13,736 rentable square feet of the Premises (the "Subleased Premises") to
Citadel Security Software, Inc. ("Subtenant") pursuant to a separate written
sublease agreement (the "Sublease"). This letter is to evidence Landlord's
consent to the sublease of the Subleased Premises to Subtenant (the Citadel
Security Subleasing Transaction") provided that such sublease shall be subject
and pursuant to all of the covenants, terms and conditions of the Lease and, to
the extent inconsistent therewith, the following covenants and conditions, to
each of which Tenant and Subtenant expressly agree:

     1. Subtenant hereby expressly assumes and agrees to perform all of the
covenants, duties and obligations of Tenant under the Lease with respect to the
Subleased Premises, and Subtenant shall be jointly and severally liable therefor
along with Tenant, except that the rent and other obligations of Subtenant shall
be as set forth in the Sublease (it being understood that Section 8(A) of the
                                                          ------------
Sublease provides that certain provisions of the Lease are inapplicable as to
the Subtenant).

     2. The Subleased Premises shall not be used for a usage different from the
usage provided in the Lease.

     3. Tenant will remain directly and primarily liable for the performance of
all of the covenants, duties and obligations of Tenant under the Lease
(including, without limitation, the obligation to pay all rental and other sums
provided to be paid), and Landlord shall be permitted to enforce the provisions
of the Lease as they relate to the Subleased Premises against Tenant and/or
Subtenant and/or any assignee, subtenant, concessionaire, licensee or other
transferee without demand upon or proceeding in any way against any other
person.

     4. Landlord's consent to the sublease of the Subleased Premises to
Subtenant shall not be deemed a consent to any other or subsequent transaction.

     5. Nothing contained in this letter agreement shall:

          (a) operate as a consent to or approval of or ratification by the
Landlord of any of the provisions of the Sublease or as a representation or
warranty by Landlord, and Landlord shall not be bound or estopped in any way by
the provisions of the Sublease; or

          (b) be construed to modify, waive or affect (i) any of the provisions,
covenants or conditions contained in the Lease, (ii) any of Tenant's obligations
under the Lease, or (iii) any rights or remedies of Landlord under the Lease or
otherwise enlarge or increase Landlord's obligations or liabilities, or Tenant's
rights, under the Lease or otherwise; or

Exhibit "F" - Landlord's Consent to Sublease - Page 1

<PAGE>

          (c) be construed to waive any present or future breach or default on
the part of Tenant under the Lease. In case of any conflict between the
provisions of this letter agreement and the provisions of the Sublease, the
provisions of this letter agreement shall govern.

     6. The Sublease shall be subject and subordinate at all times to the Lease
and all of its provisions, covenants and conditions.

     7. Section 15.202 of the Office Lease Agreement is hereby deleted in its
entirety and Tenant shall, at Tenant's sole cost and expense, remove Tenant's
wall signage in a good and workmanlike manner and repair all damage cause by
such removal.

     8. In conjunction with Landlord's consent to the Citadel Security
Subleasing Transaction, Landlord waives and releases its right to recapture the
Subleased Premises or terminate the Lease with respect to the Citadel Security
Subleasing Transaction as provided in Section 11 of the Lease. Landlord
acknowledges that, to Landlord's actual current knowledge, (i) no default or
Event of Default has occurred under the Lease, and (ii) no event or omission has
occurred that with the expiration of any time period could become a default or
Event of Default under the Lease.

          Please evidence your consent to the foregoing by executing this letter
in the space provided below, and return an executed counterpart hereof to the
undersigned.

                                        Sincerely,

                                        SWS SECURITIES, INC.,
                                        a Texas corporation


                                        By:
                                           -------------------------------------
                                        Name:
                                             -----------------------------------
                                        Title:
                                              ----------------------------------

                                        CITADEL SECURITY SOFTWARE, INC.,
                                        a                 corporation
                                          ---------------


                                        By:
                                           -------------------------------------
                                        Name:
                                             -----------------------------------
                                        Title:
                                              ----------------------------------

AGREED TO AND ACCEPTED
this         day of March, 2002.
     -------

NORTHPARK CENTRAL - VEFII, L.P.,
a Georgia limited partnership

By:  NORTHPARK VEFII SUB, INC.,
     a Georgia corporation,
     its sole general partner


     By:
        -------------------------------------
     Name:
          -----------------------------------
     Title:
           ----------------------------------

Exhibit "F" - Landlord's Consent to Sublease - Page 2