<PAGE>   1

                                                                   EXHIBIT 10.23
                              ASSIGNMENT OF LEASE
      [Nextpage, L.C./Caldera Systems, Inc./Thrushwood Properties, L.C.]

     THIS ASSIGNMENT (this "Assignment") is entered into as of the 21 day of
January, 2000, among (i) NEXTPAGE, L.C., a Utah limited liability company
("Assignor"), whose address is 5072 N. 300 W., PROVO, UT 84604 (ii) CALDERA
SYSTEMS, INC., a Utah corporation ("Assignee"), whose address is 240 West
Center Street, Orem, Utah 84057, and (iii) THRUSHWOOD PROPERTIES, L.C., a Utah
limited liability company ("Landlord"), whose address is 1149 West Center
Street, Orem, Utah 84057.

     FOR GOOD AND VALUABLE CONSIDERATION, the receipt and sufficiency of which
are acknowledged, the parties agree as follows:

     1.   Definitions. As used in this Assignment, each of the following terms
shall have the indicated meaning:

          1.1.  "Lease" means the Lease Agreement, dated October 9, 1997,
entered into between Landlord, as landlord, and Complete Data Solutions, the
predecessor in interest to Assignor, as tenant, covering the Premises, a copy
of which is attached as Exhibit A, which has been assigned to Assignor pursuant
to the instrument attached as Exhibit A.1.

          1.2.  "Premises" means the premises located at 1123 and 1125 W.
CENTER ST., Orem, Utah, crosshatched on the site plan attached as Exhibit B.

     2.   Assignment; Assumption. Assignor assigns to Assignee all of Assignor's
right, title and interest as the tenant under the Lease. Assignee accepts such
assignment and assumes and agrees to perform all of the obligations to be
performed by the tenant under the Lease, but only to the extent such
obligations first arise on or after the date of this Assignment.

     3.   Indemnification. Assignor shall indemnify, defend and hold harmless
Assignee from and against all claims, liabilities, losses, damages, costs and
expenses (including, without limitation, attorneys' fees) caused by the failure
of Assignor to timely pay or perform any obligation required to be paid or
performed by the tenant under the Lease prior to the date of this Assignment.
Assignee shall indemnify, defend and hold harmless Assignor from and against
all claims, liabilities, losses, damages, costs and expenses (including,
without limitation, attorneys' fees) caused by the failure of Assignee to
timely pay or perform any obligation required to be paid or performed by the
tenant under the Lease on or after the date of this Assignment.

     4.   Landlord's Consent. Landlord consents to the assignment and
assumption of the Lease set forth in Paragraph 2 of this Assignment.
<PAGE>   2
 5.   Estoppel. Assignor and Landlord certify to Assignee as follows:

          5.1. Lease. The Lease is in full force and effect and has not been
amended, modified or supplemented in any respect, either orally or in writing,
and is the only agreement relating to the Premises entered into between
Assignor and Landlord.

          5.2. Lease Terms. The term of the Lease and the obligation of
Assignor to pay rent under the Lease commenced on June 16, 1998 and will expire
on June 15, 2002. The monthly rent payable under the Lease is $8,990 per month.
Rent under the Lease has been paid for the period ending January 31, 2000.

          5.3. No Default. Neither Assignor nor Landlord is in default in any
manner in the performance of any of their respective obligations under the
Lease, and no circumstance exists which, with the passage of time or the giving
of notice or both, would constitute such a default.

     6.   Clarification.

          6.1. Authorized Use. Pursuant to Paragraph 2 of the Lease, Landlord
consents to the use of the Premises for general office purposes.

          6.2. Repair of Premises. The intent of Paragraph 4 of the Lease is
that Landlord is responsible for any necessary repairs to the roof, foundation,
walls and other structural elements and to the heating, cooling and plumbing
systems (other than minor, routine servicing, such as clearing clogged restroom
fixtures) of the building comprising a portion of the Premises.

          6.3. Removal of Improvements. Notwithstanding anything to contrary
contained in Paragraphs 6 or 11 of the Lease or any other provision of the
Lease, Assignee shall have no responsibility to remove any improvements located
in the Premises, or to make any repairs or restoration to the Premises with
respect to conditions existing, as of the date of this Assignment.

          6.4. Certain Improvements. All obligations of the tenant under
Paragraph 28 of the Lease have previously been fulfilled.

     7.   General Provisions. This Assignment shall inure to the benefit of,
and be binding on, the parties and their respective successors and permitted
assigns. This Assignment shall be governed by, and construed and interpreted in
accordance with, the laws (excluding the choice of laws rules) of the State of
Utah. This Assignment may be executed in any number of duplicate originals or
counterparts, each of which when so executed shall constitute in the aggregate
but one and the same document. Each exhibit referred to in, and attached to,
this Assignment is an integral part of this Assignment and is incorporated in
this Assignment by this reference.

                                      -2-
<PAGE>   3
     THE PARTIES have executed this Agreement on the respective dates set forth
below, to be effective as of the date first set forth above.


                                        ASSIGNOR:

                                        NEXTPAGE, L.C.


                                       By     /s/ MATTHEW F. BIRDWELL
                                          ----------------------------------

                                        Its    CFO
                                           ---------------------------------

                                        Date   1/21/00
                                            --------------------------------


                                        ASSIGNEE:

                                        CALDERA SYSTEMS, INC.


                                        By   /s/ RANSOM H. LOVE
                                          -------------------------------------
                                        Its  President & CEO
                                           ------------------------------------

                                        Date 1/21/00
                                            ------------------------------------


                                        LANDLORD:

                                        THRUSHWOOD PROPERTIES, L.C.

                                        By     /s/ STEVEN R. SKABELUND
                                          ----------------------------------
                                             Steven R. Skabelund
                                             Member

                                        Date            1-21-00
                                            --------------------------------

                                        By     /s/ T. JEFFERY COTTLE
                                          ----------------------------------
                                             T. Jeffery Cottle
                                             Member

                                        Date            1-21-00
                                            --------------------------------
                                      -3-





<PAGE>   4

                                   EXHIBIT A

                                       to

                              ASSIGNMENT OF LEASE


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


                                     LEASE

     The Lease is attached and consists of seven (7) pages.
<PAGE>   5
                                LEASE AGREEMENT

     THIS LEASE AGREEMENT is made and entered into this 9th day of October,
1997, by and between THRUSHWOOD PROPERTIES, L.C., (hereinafter called
"Lessor"), and COMPLETE DATA SOLUTIONS (hereinafter called "Lessee").

                                  WITNESSETH:

     In consideration of the mutual covenants and promises to observe the terms
and conditions contained herein and for other good and valuable consideration,
the receipt and sufficiency of which is hereby acknowledged, it is agreed by
the parties hereto as follows:

                                  I.  PREMISES

     Lessor hereby agrees to lease to Lessee and Lessee hereby takes and leases
from Lessor the proposed space (herein called "Premises") the property and
proposed building located directly east of 1149 and 1143 West Center, Orem,
Utah 84057. The Lessor hereby acknowledges that it has clear title to the
property that the Premises will be built on. The Lessor has also presented to
Lessee a site plan and preliminary architectural drawing to the Premises and
that the Lessee's rights hereunder shall not be subordinate to any other party
for so long as the Lessee shall be current on lease payments. The Lessor shall
do everything reasonable to make the exterior and interior of the proposed
building conform to the needs of the Lessee.  The Premises shall include
showers and a drinking fountain.

                                   II.  TERM

     The lease term shall be for a period of four years commencing on
approximately April 1st, 1998 and extending for a four year period from such
date. The term beginning on the date of completion of the construction of the
building.

                      III.  TERMS AND CONDITIONS OF LEASE

     This Lease is made on the following terms and conditions which are
expressly agreed to by Lessor and Lessee:

     1.   Lease Payments.  Lessee agrees to pay as lease payments to Lessor, at
the address specified in this Lease or at such other place as Lessor may from
time to time designate in writing, the sum of $8,990.00 per month with such
lease payments being made on the 1st day




                                       1
<PAGE>   6
of each calendar month during the term of this lease. The building shall be
approximately 8994 square feet.

          (a)  Late charges. In the event Lessee shall fail to pay said lease
payment on the due date or within five (5) days thereafter, a late charge of
five percent (5%) of the delinquent amount may, at the Lessor's discretion, be
added to said lease payment and paid to the Lessor together therewith. In
addition to the 5% late fee, any and all lease payment (including the 5% late
fee) remaining unpaid more than one calendar month, shall bear interest at the
rate of 1.75% per month, or any portion thereof, until paid, including any time
following judgement for said amounts.

          (b)  Adjustment to Lease Payments. The monthly lease payment shall be
not be adjusted but shall remain the same during the entire lease period.

          (c)  Triple Net Lease. This lease shall be a triple net lease as set
forth in this Agreement.

     2.   Authorized Use. Lessee shall use the leased Premises for the
operation of the Lessees Computer consulting business and for no other purpose
without the written consent of Lessor first being obtained.

     Lessee shall not commit or knowingly permit any waste on the Premises and
shall not knowingly permit any part of the Premises to be used for any unlawful
purpose. Lessee will comply with all applicable federal, state and local laws,
ordinances and regulations relating to the Premises and its use and operation
by Lessee. Lessee will maintain Premises in safe condition so as not to cause
harm to Lessor, Lessee or patients of either, or any persons using the Premises.

     3.   Fire and Casualty Insurance. It shall be the responsibility of the
Lessee to insure his equipment, furniture, fixtures and other personal property
with a Lessee's policy and Lessor shall have no responsibility with respect to
any losses of the same.

     Lessor shall insure the Premises exclusive of Lessee's equipment,
furniture, fixtures and other personal property against the peril of fire and
other occurrences as set forth in the insurance policy.

     Lessee will not permit the Premises to be used for any purpose which would
render the insurance thereon void or cause cancellation thereof or render the
insurance risks more hazardous.

     4.   Repair and Care of Premises. Lessee shall be responsible for all
repairs to the Premises. However, any repair respecting the structural
integrity of the building such as the roof, foundation, walls shall be the sole
responsibility of the Lessor. Repairs shall include those repairs necessary for
the roof, wall and foundation of the building as well as repairs to the





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<PAGE>   7
heating and cooling systems of the Premises. Any repair to the plumbing system
shall be considered a repair the Lessee shall be responsible for all other
repairs and upkeep of the Premises.

     5.   Utilities and other costs. Lessee shall pay for gas, electricity,
water and sewer to the Premises. Lessee shall pay all costs and charges for
installments, service, maintenance and use of telephones and telephone
equipment in and about the Premises. Lessee shall be responsible for its own
insurance on its merchandise, equipment and fixtures. The Landlord shall be
responsible for the grounds and parking lot.

     6.   Alteration of Building and Installation of Fixtures or Other
Appurtenances. Lessee may with written consent of Lessor but at Lessee's sole
cost and expense and in a good and workmanlike manner, make such alterations,
improvements and repairs to the Premises, as Lessee may require for the conduct
of its business without, however, materially altering the basic character of the
building. Lessee shall have the right, without the permissions of Lessor, to
erect, at Lessee's sole cost and expense, such temporary partitions, including
office partitions, as may be necessary to facilitate the handling of Lessee's
business and to install telephone and telephone equipment and wiring, and
electrical fixtures, additional lights and wiring and other trade appliances.
Any alterations or improvements to the Premises, including partitions, all
electrical fixtures, lights and wiring, shall, at the option of Lessor become
the property of Lessor at the expiration or sooner termination of this
Lease. All installed dental equipment by the Lessor shall be the property of the
Lessee. Should Lessor request Lessee to remove all or any part of the above
mentioned items, Lessee shall remove all or any part of the above mentioned
items. Lessee shall do so prior to the expiration of this Lease and repair the
Premises as described below.

     7.   Right of Entry by Lessor. Lessee shall permit inspection of the
Premises during reasonable business hours by Lessor or Lessor's agents or
representatives for the purpose of ascertaining the condition of the Premises
and in order that the Lessor may make such repairs or perform duties as may be
required to be made by landlord under the terms of this Lease.

     8.   Assignment and Subletting. Neither this Lease nor any interest herein
may be assigned or sublet by Lessee voluntarily or involuntarily, by operation
of law, or otherwise, and neither all nor any part of the Premises shall be
sublet by Lessee without the prior written consent of Lessor; however, Lessor
agrees not to withhold its consent unreasonably for Lessee to sublet the
Premises. Notwithstanding the above the basement portion of the Premises may so
sublet to a third party provided such sub-lessee is approved by the Lessor which
such approval may not be unreasonable withheld. The Lessee shall remain
primarily responsible on the lease at all times.

     9.   Damage and Destruction. If the Premises or any part thereof shall be
damaged or destroyed by fire or other casualty, Lessor shall promptly repair
all such damage, and restore the Premises without claims, strikes and other
causes beyond Lessor's control. If such damage or destruction shall render the
Premises untenable in whole or in part, the rent shall be abated



                                       3
<PAGE>   8
wholly or proportionately as the case may be until the damage shall be repaired
and the Premises restored. If the damage or destruction shall be so extensive as
to require the substantial rebuilding of the office building containing the
Premises, the Lessee may elect to terminate this Lease by written notice to the
Lessor on or before ninety (90) days after the occurrence of such damage or
destruction.

     10.  Injuries and Property Damage. Lessee agrees to indemnify and hold
harmless Lessor of and from any and all claims of any kind or nature arising
from Lessee's use of the Premises during the term hereof, and Lessee hereby
waives all claims against Lessor for damage to goods, wares of merchandise or
for injury to persons in and upon the Premises from any cause whatsoever,
except such as might result from the negligence of Lessor or Lessor's
representatives or from failure of Lessor to perform its obligations hereunder
within a reasonable time after notice in writing by Lessee requiring such
performance by Lessor.

     11.  Surrender of Premises. Lessee agrees to surrender the Premises at the
expiration, or sooner termination, of this Lease, or any extension thereof, in
the same condition as when said Premises were delivered to Lessee, or as
altered pursuant to the provisions of this Lease, ordinary wear and tear and
damage by the elements excepted. Lessee shall remove all of its personal
property from the Premises. Lessee agrees to pay a reasonable cleaning charge
should it be necessary for Lessor to restore or cause the Premises to be
restored to the same condition as when said Premises were delivered to Lessee.
Last months rent shall be paid at the execution of this Agreement there is no
security deposit.

     12.  Holdover. Should Lessor permit Lessee to holdover the Premises or any
part thereof after the expiration of the term of this Lease, then and unless
otherwise agreed in writing, such holding over shall constitute a tenancy from
month-to-month only and shall in no event be construed as a renewal of this
Lease, and all provisions of this Lease not inconsistent with a tenancy from
month-to-month shall remain in full force and effect. During the
month-to-month tenancy, Lessee agrees to give Lessor thirty (30) days prior
written notice of its intent to vacate from Lessor. The lease payment for the
month-to-month tenancy shall be the same as provided in Article 2 above unless
Lessor determines otherwise within ten (10) days after Lessor receives notice
from Lessee of his intention to continue to occupy Premises.

     13.  Quiet Enjoyment. If and so long as Lessee pays the rents reserved by
this Lease and performs and observes all of the covenants and provisions
hereof, Lessee shall quietly enjoy the Premises, subject, however, to the terms
of this Lease, and Lessor will warrant and defend Lessee in the enjoyment and
peaceful possession of the Premises throughout the term of this Lease.

     14.  Waiver of Covenants. The Failure of any party to enforce the
provisions of this Lease shall not constitute a waiver unless specifically
stated in writing, signed by the party whose rights are deemed waived,
regardless of the party's knowledge of a breach hereunder.



                                    4
<PAGE>   9
     15.  Default in Rent -- Insolvency of Lessee. If Lessee shall default in
the payment of the rent reserved hereunder, or any part thereof, or in making
any other payment herein provided for, and any such default shall continue for
a period of thirty (30) days, or if the Premises or any part thereof shall be
abandoned or vacated; or if tenant shall be legally dismissed therefrom by or
under any authority other than Lessor; or if the leasehold estate created
hereby shall be taken on execution of by any process of law; or if Lessee shall
admit in writing its ability to pay its obligations generally as they become
due, then Lessor, in addition to any other rights or remedies it may have,
shall have the immediate right of re-entry and may remove all persons and
property from the Premises. Such property may be removed and stored in a public
warehouse or elsewhere at the cost of and for the account of the Lessee.

     Lessor may elect to re-enter, as herein provided, or Lessor may take
possession pursuant to this Lease and relet said Premises or any part thereof
for such term or terms (which may be for a term extending beyond the term of
this Lease) and at such lease payment or lease payments and upon such other
terms and conditions as Lessor in the exercise of Lessor's sole discretion may
deem advisable with the right to make alterations and repairs to said Premises.
Upon each such renting, Lessee shall be immediately liable for and shall pay to
Lessor, in addition to any indebtedness due hereunder, the costs and expenses
of such reletting including advertising costs, brokerage fees, and any
reasonable attorney's fees incurred and the cost of such alterations and
repairs incurred by Lessor, plus the amount, if any, by which the rent reserved
in this Lease for the period of such reletting (up to but not beyond the term
of the Lease) exceeds the amount agreed to be paid as rent for the Premises for
said period by such reletting. If Lessee has been credited with any rent to be
received by such reletting and such rents shall not be promptly paid to the
Lessor by the new Lessee, such deficiency shall be calculated and paid monthly
by Lessee.

     Should Lessor at any time terminate this Lease for those reasons specified
in the prior paragraph, in addition to any other remedy Lessor may have, Lessor
may recover from Lessee all damages Lessor may incur by reason of such breach,
including the cost of recovering the Premises including attorney's fees, court
costs, and storage charges and including the worth at the time of such
termination of the excess, if any, of the amount of rent and charges equivalent
to rent reserved in this Lease for the remainder of the stated term over the
then chargeable rent on the Premises for the remainder of the stated term, all
of which amounts shall be immediately due and payable from Lessee to landlord.
In no event, shall this Lease or any rights or privileges hereunder be an asset
of Lessee under any bankruptcy, insolvency or reorganization proceedings.

     16. Enforcement. In the event either party shall enforce the terms of this
Lease by suit or otherwise, the party at fault shall pay costs and expenses
incident thereto, including reasonable attorney fees and costs, including those
incurred on appeal.


                                       5
<PAGE>   10
     17.  Rights of Successors and Assigns. The covenants and agreements
contained in this Lease will apply to, inure to the benefit of, and be
binding upon the parties hereto, their heirs, distributees, executors,
administrators, legal representatives, assigns, and upon their respective
successors in interest, except as expressly otherwise herein provided.

     18.  Time. Time is of the essence with respect to this lease and every
term, covenant and condition herein contained.

     19.  Keys and Locks. Lessee shall not change locks or install other locks
on doors without written consent of Lessor who agrees not to unreasonably
withhold his consent. Lessee upon the termination of the Tenancy shall deliver
to Lessor all the keys to the offices, which shall have been furnished to
Lessee.

     20.  Construction of Lease. Words of any gender used in this Lease shall
be held to include any other gender, and words in the singular number shall
be held to include the plural when the context and facts so require.

     21.  Paragraph Headings. The paragraph headings as to the contents of
particular paragraphs herein are inserted only for convenience and are in no way
to be construed as part of such paragraph or as a limitation on the scope of the
particular paragraph to which they refer.

     22.  Governing Law. The terms of this Lease shall be governed by and
construed in accordance with Utah Law.

     23.  Contingency Regarding Use. This Lease is contingent upon there being
no restrictions, covenants, laws, ordinances, rules or regulations, which
prohibit Lessee from using the Premises for the purpose described herein.

     24.  Entire Lease. This Lease constitutes the entire agreement and
understanding between the parties hereto and supersedes all prior discussions,
understandings and agreements. This Lease may not be altered or amended except
by a subsequent written agreement executed by all of the parties hereto.

     25.  Review of Lease. The parties hereto represent that they have read and
understand the terms of this Lease, and that they have sought legal counsel
to the extent deemed necessary in order to protect their respective interests.

     26.  Lessor's Address. The Lessor's address be 1149 West Center,
Orem, Utah 84057.

     27.  Coordination with current lease. The Lessee shall be released from its
lease at 1143 West Center at the time of the occupation of the Premises. The
lease shall be prorated as of the date of occupancy. The Lessor shall purchase
the current blinds of the Lessee at an amount equal to the blinds cost.


                                       6
<PAGE>   11
     28.       Completion of Leased Premises. The Lessee shall provide 2 inch
wood blinds on the upstairs and main floor windows and 2 inch vinyl blinds on
the downstairs windows. Locks shall be provided on selected doors and all wiring
shall be done by builder at Lessee's specifications at no cost to the Lessee.
Such wiring shall include conduit and wiring comparable to what Lessee currently
has at 1143 West Center, Orem, Utah.

     IN WITNESS WHEREOF, the parties hereto have caused these presents to be
executed the day and year first above written.


LESSOR:

THRUSHWOOD PROPERTIES, L.C.


By: /s/ STEVEN R. SKABELUND
   -------------------------------------
   STEVEN R. SKABELUND, Member


By: /s/ T. JEFFERY COTTLE
   -------------------------------------
   T. JEFFERY COTTLE, Member


LESSEE:

COMPLETE DATA SOLUTIONS


By: /s/ KYLE JUDSON
   -------------------------------------
   KYLE JUDSON

By: /s/ CHRIS WORSLEY
   -------------------------------------
   CHRIS WORSLEY

By: /s/ PAUL MECHAM
   -------------------------------------
   PAUL MECHAM




                                       7
<PAGE>   12
                                  EXHIBIT A.1

                                       to

                              ASSIGNMENT OF LEASE

_______________________________________________________________________________

                             ASSIGNMENT INSTRUMENT

     The assignment instrument is attached.
<PAGE>   13


                                   EXHIBIT B

                                       to


                              ASSIGNMENT OF LEASE

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


                                    PREMISES

     The Premises are crosshatched on the attached diagram which consists of one
(1) page.













                          [DIAGRAM OF LEASED PREMISES]
<PAGE>   14
                          [DIAGRAM OF LEASED PREMISES]