<PAGE>
                                                                   Exhibit 10.23
LEASE ADDENDUM ONE

ADDITIONAL RENT

               The provisions of Paragraph 4 of the Lease are as follows:

               (a)  Any amounts required to be paid by Tenant under this 
Lease Addendum and any charges or expenses incurred by Landlord on behalf of 
Tenant under the terms of this Lease shall be considered Additional Rent 
payable in the same manner and upon the same terms and conditions as the Rent 
reserved hereunder. Any failure on the part of Tenant to pay such Additional 
Rent when and as the same shall become due shall entitle Landlord to the 
remedies available to it for nonpayment of Rent.

               (b)  In addition to the services to be provided by Landlord 
pursuant to Paragraph 12 of this Lease, Landlord shall provide the following 
additional services to Tenant (the costs of which shall be included in 
Operating Expenses):

               (i)  If elevators are installed in the Property, Landlord 
shall provide automatically operated elevator service.

               (ii) Landlord shall provide replacement of light tubes or 
bulbs for building standard lighting fixtures. (All light tube or bulb 
replacements for special nonstandard light fixtures shall be furnished and 
installed by Tenant at Tenant's direct expense.)

               Landlord shall furnish to the Demised Premises during normal 
business hours (i.e., weekdays 7:00 a.m. to 11:00 p.m., and Saturdays 7:00 
a.m. to 12:00 noon, excluding Fedei7al and State holidays) electric current 
for lighting and operation of normal desk-type office machines (such as 
personal computers, typewriters, facsimile machines and other similar office 


<PAGE>

machines), water, lavatory supplies, and heating, ventilating and 
air-conditioning (HVAC) to the Demised Premises.  Tenant shall provide for 
its own telephone service (including any charges connected therewith) in the 
Demised Premises at the commencement of the Term of this Lease, or Tenant's 
occupancy, whichever shall first occur.

               (iv) Landlord shall provide routine maintenance and repair of 
the common areas of the Property, including landscaping maintenance, snow and 
rubbish removal, re-painting and cleaning for all public areas and special 
service areas of the Property, in the manner and to the extent deemed by 
Landlord to be standard for comparable buildings in the jurisdiction where 
the Property is located.

                    (v) Landlord shall provide a central trash dumping
are a .

               (c)  Commencing with the first day of the second lease year, 
and for each subsequent calendar year or portion thereof for the Term, Tenant 
agrees to pay to Landlord as Additional Rent its Pro Rata Share (as 
hereinafter defined) of any increase in Operating Expenses, Taxes and 
Assessments and Costs of Demised Premises Services paid during such calendar 
year above the Base Costs of Operating Expenses, Taxes and Assessments and 
Costs of Demised Premises Services.  The annual portion of such excess above 
Base Costs of Operating Expenses, Taxes and Assessments, and Costs of Demised 
Premises Services which is attributable to increases in Costs of Demised 
Premises Services shall be reasonably determined by Landlord.  In order for 
Tenant to be required to pay any increase in Operating Expenses, Taxes and 
Assessments and Costs of Demised Premises Services for any year, the actual 
amount of Operating Expenses, Taxes and Assessments and Costs of Demised 
Premises Services in the aggregate must exceed the Base Costs of Operating 
Expenses, Taxes and Assessments and Cost of Demised Premises Services in the 
aggregate.
 
<PAGE>

0



               Foy purposes of this Lease Addendum One, the first day of the 
second lease year as to the entire Demised Premises shall be that date which 
is the first anniversayy of the Lease Commencement Date with respect to the 
poytion of the Demised Premises other than the Broker Power Space (said 
portion of the Demised Premises other than the B@okey Powey Space is being 
delivered to Tenant upon execution of this Lease and the Lease Commencement 
Date therefor shall be determined pursuant to Paragraph 2(b) of this Lease).

               (d)  For purposes of this Lease:

               "Base Costs of Operating Expenses, Taxes and Assessments and 
Costs of Demised Premises Services" shall mean Operating Expenses, Taxes and 
Assessments and Costs of Demised Premises Services incurred during the 1997 
calendar year under the Lease.

               (ii) "Pro Rata Share" shall mean 100'-. of increases in Costs 
of Demised Premises Seyvices (i.e., Tenant shall pay the entire increase in 
the Cost of Demised Premises Services for any calendar year above the Cost of 
Demised Premises Seyvices for the first lease year under the Lease), and, as 
to Operating Expenses and Taxes and Assessments, fifty-three point 
seventy-se@en percent (53.77%), representing the ratio that the ayea of the 
Demised Premises bears to the total rentable area in the Building.

               (iii)     "Taxes and Assessments" shall mean all taxes and 
assessments and governmental charges (including personal property and real 
estate taxes), whether federal, state, county or municipal, and whether they 
be by taxing districts or authorities presently taxing the Property or by 
others subsequently created, and any other taxes and assessments (including 
franchise taxes) attributable to the Property or its operation, whether or 
not directly paid by Landlord, excluding, however, federal and state taxes on 
income, unless such income taxes replace real estate

taxes.  Taxes and Assessments shall be the amount due in cash for any calendar
year and shall not be determined on an accrual or fiscal year basis.  It is
agreed that Tenant shall be responsible for ad valorem taxes on its personal
property and on the -value of leasehold improvements to the extent that same
exceed building standard allowances.

               (iv) "Operating Expenses" shall mean all costs as determined 
by Landlord to be necessary to operate the Property, to the extent not 
separately billed to and paid by Tenant, of operation, maintenance and repair 
(except structural repairs) of the Property and its appurtenances and shall 
include, but will not be limited to: all insurance premiums, the cost of 
labor (including direct and indirect labor overhead), materials and services 
foy the operation, maintenance and repair of the Property and its 
appurtenances (including common areas, service roads and parking areas); gas, 
electricity and other utilities; water and sewer charges; maintenance and 
repair of heating, ventilating and air-conditioning; trash, refuse and 
rubbish


<PAGE>

disposal; snow removal; license, permit and inspection fees (whether 
denominated a fee, a tax or otherwise and whether based on gross receipts or 
otherwise); management fees to the extent not in excess of three percent (3%) 
of gross revenues from the Building during any Lease Year; janitorial 
services; maintenance and service contracts; landscaping costs; the costs of 
parking lot lighting; the cost of watchmen, guards, and any personnel engaged 
in the operation, maintenance or repair of the Property and its appurtenances 
together with payroll taxes and employee benefits applicable thereto; and 
supplies.  Notwithstanding anything in this Lease to the contrary, Operating 
Expenses shall not include depreciation of the Building of which the Demised 
Premises are a part or equipment therein; loan payments; executive salaries; 
interest and amortization of funds borrowed

2

<PAGE>
0


by Landlord, whether secured or unsecured; leasing commissions

incurred       in procuring tenants for the Building; income, excess

profits,       franchise taxes or other such taxes imposed on or
measured       by the income of Landlord from the operation of the

Building; Taxes and Assessments; Cost of Demised Premises Services; original
construction costs of the Building;
reserves       for repairs, maintenance and replacements, until
utilized       for costs which are included in Operating Expenses;,
costs or       expenses associated with leasing space in the Building
or the sale of any interest in the Building, including, without limitation,
advertising and marketing; commissions or any amounts paid for or on behalf of a
Tenant such as space planning, moving costs, rental and other tenant
concessions; ground 2:ents; salaries, wages, or other compensation paid to
employees of any property management organization whose salaries are covered by
a management fee; amounts paid to any partners, shareholder, officer or director
of Landlord, for salary or other compensation; costs of electricity outside
normal business hours sold to tenants of the Building by Landlord or any other
special services to tenants if Landlord receives reimbursement from such tenants
as an additional charge; expenses for repairs, replacements or improvements
arising from the initial construction of the Building to the extent such
expenses are reimbursed to Landlord by virtue of warranties from contractors or
suppliers; any amounts paid to any person, firm or corporation related to or
otherwise affiliated with Landlord or any general partner, officer or director
of Landlord or any of its general partners, to the extent the same exceeds
arms-length competitive prices paid in the Manassas, Virginia area for the
services or goods provided; attorneys' fees and accountants' fees in connection
with any disputes, controversies or defaults under leases of other tenants
regarding the payment of 3fent; costs of repairs incurred by reason of fire or
other casualty or condemnation to the extent Landlord receives compensation
therefor through proceeds of insurance or condemnation awards; cost of
renovating or otherwise improving space for new tenants or in renovating space
vacated by any tenant; costs relating to maintaining Landlord's existence,
either as a corporation, partnership, or other entity, such as trustee's fees,
annual fees, partnership organization or administration expenses, deed
recordation expenses, and legal and accounting fees (other than with respect to
Building operations); interest or penalties arising by reason of Landlo2:dls
failure to timely pay any Operating Expenses when due, unless at the time of any
such failure Tenant is in default in the payment of any Rent then due under this
Lease; costs incurred for the operation (but not the maintenance, repair or
replacement) of any portion of any parking area of the Building, or compensation
paid to clerks, attendants, salespersons or other persons on or in commercial
concessions operated in the Building; and capital costs incurred to remove any
hazardous or toxic wastes, materials or substances, placed on the Property by
Landlord, from either the Building or the Property, but shall include
amortization, with reasonable interest, of capital items which reduce Operating
Expenses or are required by governmental authority


<PAGE>

pursuant to @equ3 . elements arising after the date of this Lease.

               In the event that, during any calendar year or portion thereof 
during the Term, Landlord shall furnish any utility or service which is 
included in the definition of Operating Expenses to less than ninety-five 
percent (956) of the rentable area of the Building because (i) less than all 
of the rentable area of the Building is occupied, (ii) any such utility or 
service is not desired or required by any tenant, or (iii) any tenant is 
itself obtaining or providing any such utility or service, then the operating 
Expenses for such calendar year shall be increased to equal the total 
expenses that Landlord reasonably estimates it would have incurred if 
Landlord had provided all such utilities and services to ninety-five percent 
(9S-6) of the rentable area of the Building for the entire calendar year.  For

3
<PAGE>
               0                           0


example, if the average occupancy rate of the Building during a calendar year is
eighty percent (80@), the janitorial contracto@'s charges aye $1.00 per occupied
rentable square foot per year, and the Building contains one hundred thousand
(100,000) rentable square feet of space, then it would be reasonable for
Landlord to estimate that, if the Building had been one hundred percent (loo-.)
occupied during the entire calendar year, janitorial charges for such calendar
year would have been Ninety-Fi@e Thousand Dollars ($95,000) and to compute the
Operating Expenses for such calendar year accoydingly.  In no event shall the
provisions of this paragraph be used to enable Landlord to collect from the
tenants of the Building more than one hundred percent (100'@) of the costs and
expenses incurred by Landlord in managing, opeyating and maintaining the
Building and the Land, or to require Tenant to pay Operating Expenses for vacant
leasable area in the Building.

               (v)  "Demised Premises Sei7vices" means all services provided 
by Landlord under this Lease for maintenance and repair of and services to 
the Demised Premises, and the costs and expenses of Demised Premises Seyvices 
are referred to herein as the "Costs of Demised Premises Services." Demised 
Premises Services shall include, without limitation, regularly scheduled 
reasonable cleaning service twice each day (Monday thyough Friday) to the 
Demised Premises, the first such cleaning to be provided between S:00 p.m. 
and 6:30 p.m. and the second such cleaning to be provided after 11:00 p.m. 
and befoye 7:00 a.m. Monday through Friday.
 



(e) Landlord shall endeavor to give to   give such statement by said date shall
Tenant on or before the fiyst day of     not Landlord of its right to require an
April of each calendar year a statement  Rent. Notwithstanding the foregoing, 
of the increase in the Additional Rent   if delivey a statement of the increase 
payment by Tenant hereunder, but         in the first day of October of a 
failure by Landlord to constitute a      calenday year, the right, by prior
waivey by increase in Additional         written notice to
Landlord shall fail to Additional
Rent by the then Tenant shall have


<PAGE>


Landlord, to request said statement from Landlord and if said statement is not
delivered to Tenant within forty-five (45) days of Tenant's written request,
then and only then, shall Landlord have waived its right to require an increase
in Additional Rent under this Lease Addendum one for the calendar yeay in
question.

               Upon receipt of the first such statement, Tenant shall pay, in 
full, the total amount of the increase due.  In addition, for the then 
current year, an amount equal to 105'6 of any such increase shall be used as 
an estimate for said cuy@ent year and this amount shall be divided into 
twelve (12) equal monthly installments and Tenant shall pay to Landlord 
concurrently with the regular monthly Rent payment next due following the 
receipt of such statement, an amount equal to one (1) monthly installment. 
subsequent installments shall be payable concurrently with the regular 
monthly Rent payments for the balance of that calendar year and shall 
continue until the next year's statement is @ende@ed. If the next or any 
succeeding year results in a greater amount due -in respect of Taxes and 
Assessments and Opeyating Expenses and Costs of Demised Premises Services, 
then upon receipt of a statement from Landlord, Tenant shall pay a lump sum 
equal to such increased amount, less the total of the monthly installments of 
estimated increases paid in the previous calendar year for which comparison 
is then being made; and the estimated monthly installments to be paid for the 
next calendar year, following said comparison calendar year, shall be 
adjusted to reflect 10SP6 of such increase in the manner set forth above. if 
for any year Tenant's Pro Rata Share shall be less than estimated amounts 
paid by Tenant in the immediately pyeceding calendar year, then upon receipt 
of Landlord's statement, any excess payment made by Tenant on the monthly 
installment basis provided above shall be credited toward the

                                          4
                                            
<PAGE>
                                          0
                                           


next monthly Rent falling due and the estimated monthly installments of Taxes
and Assessments and Operating Expenses and Costs of Demised Premises Services to
be paid shall be adjusted to reflect such lower Taxes and Assessments and
Operating Expenses and Costs of Demised Premises Services for the most recent
comparison calendar year, but not less than the Base Costs thereof.  Upon
termination of this Lease, any money owed by one party to the other shall be
promptly paid.

               (f)  Each statement provided by Landlord pursuant to this 
Lease Addendum shall be prima facie correct, unless manifestly in error.  
Tenant shall have the right to request that Landlord provide, at Tenant's 
expense, an audit of Landlo@d's books and records relating to the statement.  
In order to exercise such right Tenant must notify Landlord of Tenant's 
desire to do so within six (6) months after Tenant's receipt of Landlord's 
statements for the preceding year.  Such audit shall be conducted at 
Landlo2:dls Building management office in the Building, during normal 
business hours, within sixty (60) days after Tenant's notice requesting such 
audit.  Any such audit shall be made only by an auditor hired by Tenant who 
is a Certified Public Accountant ("CPA") and who is employed on other than a 
contingent fee basis.  Tenant shall notify Landlord of the results of such 
audit in writing.  In the event that any such audit reveals an overstatement 
or understatement of Tenant's Pro Rata Share of increases in Operating 
Expenses, Taxes and Assessments, c3@ Cost of Demised Premises Services for 
the preceding year, and such overstatement or understatement as revealed 
thereby is agreed by Landlord to be, or is conclusively determined by a court 
of competent jurisdiction to be, correct (and all periods for appeal have 
expired and no appeal is pending), then Tenant shall pay to Landlord its Pro 
Rata Share of any underpayment within thirty (30) days after the date such 
audit is agreed to by Landlord or is conclusively determined by a court of 
competent jurisdiction to be correct (and all periods for appeal have expired 
and no appeal is pending), and Tenant shall have the right to a credit or 
refund, at Tenant's option, in the amount of Tenant's percentage of any 
overpayment.  Such credit shall be applied against the Rent next coming due 
and payable hereunder. In the event that such audit reveals that Operating 
Expenses, Taxes and Assessments, or Cost of Demised Premises Services, or any 
combination of the three were overstated in the amount of three percent (3-.) 
or more, then Tenant shall have the right to receive from Landlord a 
reimbursement of the reasonable costs and expenses incurred by Tenant in 
connection with such audit of Operating Expenses, Taxes and Assessments, or 
Cost of Demised Premises Services or any combination of

                                          2
<PAGE>

the three.  In the event that such audit reveals that Operating Expenses, 
Taxes and Assessments, or Cost of Demised Premises Services or any 
combination of the three were not overstated or were overstated in the amount 
of five percent (5-.) or less, then Landlord shall have the right to receive 
from Tenant a reimbursement of costs and expenses incurred by Landlord in 
connection with such audit of Operating Expenses, Taxes and Assessments, or 
Cost of Demised Premises Services or any combination of the three, including, 
but not limited to, compensation for that portion, if any, of the time of 
Landlord's property management personnel which is in excess of twenty (20) 
hours.  Tenant hereby agrees (i) that none of Tenant's shareholders (or 
partners, if applicable) or Office Manager, Administrator or similarly titled 
personnel shall, or shall authorize anyone else to, initiate any discussions 
with, or respond to any requests for information from, any person as to the 
existence, status or results of any such audit and (ii) that Tenant shall 
instruct Tenant's auditor and attorney and their employees to keep the 
results of such audit in strictest confidence; provided, however, that 
Landlord hereby agrees that nothing set forth above shall preclude Tenant 
from disclosing the results of such audit (A) in any judicial or 
quasi-judicial proceeding, or pursuant to court order or discovery request, or

(B)            to any current or prospective assignee or sublessee of

                                          3

<PAGE>

 
Tenant, or (C) to any agent, representative or employee of Landlord who or which
requests the same, or (D) to any mortgagee of the Building, the Property or
both, who or which requests the same.  Pending determination of the dispute,
Tenant shall pay within ten (10) days from notice any amounts due from Tenant in
accordance with the statement, but such payment shall be without prejudice to
Tenant's position.

               If the term of this Lease ends prior to the last day of a 
calendar year, then the amount of the increase in Taxes and Assessments, 
Operating Expenses and Costs of Demised Premises Services due for that 
calendar year shall be apportioned on a per them basis so that only that 
portion attributable to the portion of the calendar year that occurs during 
the term of this Lease shall be payable by Tenant.

               (h)  In determining the amounts payable by Tenant under this 
Lease Addendum One, Landlord shall use its reasonable judgment to take into 
account adjustments for (a) disproportionate use of services and utilities by 
any tenant or tenants of the Building and (b) allocation of expenses for 
services used exclusively by a particular tenant of the Building.

               IN WITNESS WHEREOF, Landlord and Tenant have executed this 
Lease Addendum as of the date of the Lease to which this Lease Addendum is 
attached.

                                      LANDLORD:
                                           
                                                  BATTLEFIELD
                                                  BUILDING FIVE

                                                  LIMITED PARTNERSHIP,
                                                  a

                                                  Virginia limited partnership

WITNESS:                             By: Holladay Partners, Inc.,

                                                        its g         a@tne@



                                                  By:                     (SEAL)

                                                       f

                                          4


<PAGE>

                                       TENANT:
                                           
ATTEST:                              COMPUTER LEARNING CENTERS,

                                              INC., a Delaware corporation


                                              By:                      --iSEAL'


                                          6
<PAGE>
                                  LEASE ADDENDUM TWO
 
                                      EXCLUSIVE


               During the initial Term of this Lease and so long as Computer 
Learning Centers, Inc., a Delaware corporation, is in occupancy of the 
Demised Premises and is operating a -vocational computer training school in 
the Demised Premises, and is not in Default under this Lease, Landlord shall 
not, without the prior written consent of Tenant (which consent may be 
granted or denied in Tenant's sole and absolute discretion), lease any other 
space in the Building to any tenant whose primary use would be as a 
vocational computer training school.  The foregoing exclusive shall not be 
applicable to (i) any tenant at the Property that obtains a judgment or court 
order that the provisions of this Addendum are void or otherwise 
unenforceable with respect to such tenant, or (ii) any similar uses which 
exist pursuant to a valid lease or sublease with a tenant or subtenant as of 
the date of execution of this Lease.

               If Landlord is determined by a court to have entered into a 
lease after the date of this Lease which permits or falls to prohibit the 
primary use of space in the Building as a vocational computer training school 
in violation of this Lease Addendum Two, Landlord shall pay (i) its own costs 
to settle or litigate such dispute, (ii) Tenant's costs of enforcing this 
exclusive (including reasonable attorney's fees and expenses) if Tenant 
prevails in such action, and (iii) the costs of enforcing this exclusive 
against any such other tenant in the Building.  In the event of an alleged 
violation by another tenant of the Building of the use clause in its lease 
and such violation materially adversely affects Tenant's business in the 
Demised Premises, then Tenant may request that Landlord enforce the exclusive 
in this Lease Addendum Two against such other tenant, and, whether or not 
Landlord prevails, Landlord and Tenant shall each bear fifty percent (50'-.) 
of the reasonable costs actually incurred by Landlord to settle or litigate 
the dispute with such other
tenant.
WITNESS:                             LANDLORD:

                                     BATTLEFIELD BUILDING FIVE LIMITED
                                     PARTNERSHIP, a Virginia limited partnership

                                     By:  Holladay Part rs, Inc., its General P@

                                                        py-  A    (Seal)
                                                              I)ct i @o
                                                     Its- e --,d e,@+
                                          6

<PAGE>
                 ATTEST:                       TENANT:

[Corporate Seal]                     COMPUTER LEARNING CENTERS, INC.,
                                     Delaware corporation


                                     By:
                                     Name

                                     Its: vlo-- @o

                                                                 - - - -------

                                          7