<PAGE>

                                                                   Exhibit 10.28

                                AMENDMENT NO. 11
                                       TO
                      AMENDED AND RESTATED CREDIT AGREEMENT

      THIS AMENDMENT NO. 11 TO AMENDED AND RESTATED CREDIT AGREEMENT, dated as
of December 8, 2000 ("this Amendment ") among:

            (i) MCSi, Inc., a Maryland corporation which is the successor by
      merger to Miami Computer Supply Corporation, an Ohio corporation (herein,
      together with its successors and assigns, the "Borrower");

            (ii) the financial institutions listed on the signature pages hereof
      (the "Lenders");

            (iii) NATIONAL CITY BANK, a national banking association, as a
      Lender and as Documentation Agent; and

            (iv) PNC BANK, NATIONAL ASSOCIATION, a national banking association,
      as a Lender, the Swing Line Lender, a Letter of Credit Issuer and as
      Administrative Agent (the "Administrative Agent") for the Lenders under
      the Credit Agreement:

      PRELIMINARY STATEMENTS:

(1) The Borrower, the Lenders named therein, and the Administrative Agent
entered into the Amended and Restated Credit Agreement, dated as of December 1,
1998, as amended by Amendment No. 1 thereto, dated as of March 31, 1999,
Amendment No. 2 thereto, dated as of April 19, 1999, Amendment No. 3 thereto,
dated as of August 13, 1999, Amendment No. 4 thereto, dated as of August 31,
1999, Amendment No. 5 thereto, dated as of December 20, 1999, Amendment No. 6
thereto, dated as of January 10, 2000, Amendment No. 7 thereto, dated as of
February 4, 2000, Amendment No. 8 thereto, dated as of April 30, 2000, Amendment
No. 9 thereto, dated May 31, 2000 and Amendment No. 10 thereto, dated as of
September 27, 2000 (as so amended, the "Credit Agreement"; with the terms
defined therein, or the definitions of which are incorporated therein, being
used herein as so defined).

(1) Pursuant to Amendment No. 10 to Amended and Restated Credit Agreement, dated
as of September 27, 2000 ("Amendment No. 10"), the Credit Agreement was amended
to provide, among other things, for a temporary increase in the Total General
Revolving Commitment from $160,000,000 to $170,000,000, and the Lenders made
General Revolving Loans to the Borrower reflecting usage of such temporary
increase (such General Revolving Credit Loans reflecting such usage are referred
to herein as the "September Bridge Loans").

      (3) The September Bridge Loans having been paid in full, the parties
hereto desire to amend the Credit Agreement to provide for a temporary increase
in the Total General Revolving Commitment from $160,000,000 to $181,000,000, and
to otherwise amend certain provisions of the Credit Agreement, all as more fully
set forth below.

      NOW, THEREFORE, the parties hereby agree as follows:

<PAGE>

1. AMENDMENTS, ETC.

(a) Temporary Increase in Total General Revolving Commitment, etc. Effective
only during the period from December 8, 2000 through the earlier of (i) March
31, 2001, or (ii) the date the Total General Revolving Credit Commitment is
terminated (such earlier date, the "Temporary Increase End Date"), the Total
General Revolving Commitment shall, subject to the terms and conditions set
forth herein, be increased from $160,000,000 to $181,000,000, and the General
Revolving Commitments of the Lenders set forth in Annex I to the Credit
Agreement shall be amended to reflect the following:

<TABLE>
<CAPTION>
Lender                                             General Revolving Commitment
------                                             ----------------------------
<S>                                               <C>
PNC Bank, National Association                    $ 30,375,000.00
National City Bank                                $ 28,906,250.00
Key Corporate Capital Inc.                        $ 28,906,250.00
Bank One, Indiana, N. A.                          $ 25,000,000.00
Firstar Bank, N. A.                               $ 28,906,250.00
The Huntington National Bank                      $ 28,906,250.00
The Provident Bank                                $ 10,000,000.00
                                                  ---------------
        Total                                     $181,000,000.00
                                                  ===============

</TABLE>

(a) For the avoidance of doubt, it is noted that the Borrower has the right to
make permanent reductions in the amount of the Total General Revolving
Commitment in accordance with the provisions of section 4.2(c) of the Credit
Agreement. If as of 5:00 P. M. (local time at the Notice Office of the
Administrative Agent) on the Temporary Increase End Date, the Total General
Revolving Commitment shall not previously have been permanently reduced to
$160,000,000 or less by a voluntary and permanent reduction made in accordance
with the provisions of section 4.2(c) of the Credit Agreement, then effective as
of such time on the Temporary Increase End Date, the Total General Revolving
Commitment shall be automatically and permanently reduced from $181,000,000 to
$160,000,000, and Annex I to the Credit Agreement shall be amended to reflect
the reduced General Revolving Commitments of the Lenders as follows:

<TABLE>
<CAPTION>
Lender                                             General Revolving Commitment
------                                             ----------------------------
<S>                                                <C>
PNC Bank, National Association                     $ 25,000,000
National City Bank                                 $ 25,000,000
Key Corporate Capital Inc.                         $ 25,000,000
Bank One, Indiana, N. A.                           $ 25,000,000
Firstar Bank, N. A.                                $ 25,000,000
The Huntington National Bank                       $ 25,000,000
The Provident Bank                                 $ 10,000,000
                                                   ------------
        Total                                      $160,000,000
                                                   ============
</TABLE>

(a) To the extent that General Revolving Loans outstanding under the Credit
Agreement reflect a usage of the temporary increase in the Total General
Revolving Commitment from $160,000,000 to $181,000,000 effected by this
Amendment (General Revolving Loans reflecting such usage are referred to herein
as "December Bridge Loans"), then, notwithstanding anything to the contrary
contained in the Credit Agreement, (i) the Applicable Prime Rate Margin for such
December Bridge Loans which are Prime Rate Loans and the Applicable Eurodollar
Margin for December Bridge Loans which are Eurodollar Loans shall be equal to
the Applicable Temporary Margin, as hereinafter defined, from time to time in
effect, and (ii) the default rate of interest pursuant to Section 2.7(d) of the
Credit Agreement for December Bridge Loans shall be a rate per annum equal to 2%
above the interest rate that would be applicable to December Bridge Loans that
are Prime Rate Loans. As used herein, "Applicable Temporary Margin" shall mean
(A) with respect to December Bridge Loans which are Prime Rate Loans, (1) 300
basis points on December 8, 2000 through January 30, 2001, (2) 350 basis points
on January 31, 2001 through February 28, 2001, and (3) 400 basis points on March
1, 2001 and thereafter, and (B) with respect to December Bridge Loans which are
Eurodollar Loans, (1) 450 basis points on December 8, 2000 through January 30,
2001, (2) 500 basis points on January 31, 2001 through February 28, 2001, and
(3) 550 basis points on March 1, 2001 and thereafter.

<PAGE>

(a) The only Interest Period which shall be available for a December Bridge Loan
which is a Eurodollar Loan is an Interest Period of one month, subject to
Continuation for additional Interest Periods of no longer than 1 month as
provided in section 2.8 of the Credit Agreement. With respect to a December
Bridge Loan that is a Eurodollar Loan, no Interest Period may be selected that
would end after the Temporary Increase End Date.

(a) The Borrower may only request December Bridge Loans on December 8, 2000.
Once a December Bridge Loan is incurred, it may not be prepaid except in
connection with a contemporaneous prepayment of all other December Bridge Loans
and a contemporaneous permanent reduction of the Total General Revolving
Facility to $160,000,000 or less, effected in accordance with the applicable
provisions of the Credit Agreement. Any December Bridge Loan that is outstanding
on the Temporary Increase End Date shall be repaid in full on the Temporary
Increase End Date, together with accrued interest and any breakage compensation
payable pursuant to section 2.10. Once a December Bridge Loan has been repaid it
may not be reborrowed.

      (f) The proceeds of the December Bridge Loans shall be used by the
Borrower to (i) finance the AV Associates Acquisition, as defined in section 1.4
of this Amendment, up to an aggregate principal amount not to exceed $6,500,000,
and (ii) for general corporate purposes.

1.1. Pricing. Effective on and as of the Amendment Effective Date, as defined in
section 3 of this Amendment, the Pricing Grid Table which appears in section
2.7(h) of the Credit Agreement is amended to read in its entirety as follows:

                               PRICING GRID TABLE
                           (expressed in basis points)

<TABLE>
<CAPTION>
======================================================================================
                  Ratio of                Applicable
          Consolidated Total Debt      Eurodollar Margin   Applicable     Applicable
                     to                   for General      Prime Rate   Commitment Fee
 Tier       Consolidated EBITDA         Revolving Loans      Margin          Rate
======================================================================================
<S>    <C>                                    <C>            <C>            <C>
       Greater than 3.50 to 1.00              275.00         125.00         50.00
VI
--------------------------------------------------------------------------------------
       Greater than 3.00 to 1.00 but          250.00         100.00         50.00
V      less than or equal to 3.50 to 1.00
--------------------------------------------------------------------------------------
       Greater than 2.50 to 1.00 but          225.00          75.00         50.00
IV     less than or equal to 3.00 to 1.00
--------------------------------------------------------------------------------------
       Greater than 2.00 to 1.00 but          200.00             50         50.00
III    less than or equal to 2.50 to 1.00
--------------------------------------------------------------------------------------
       Greater than 1.50 to 1.00 but          175.00             25         35.00
II     less or equal to 2.00 to 1.00
--------------------------------------------------------------------------------------
       Less than or equal to 1.50 to  1.00    150.00             -0-        25.00
I
======================================================================================
</TABLE>

(a) Effectiveness of Pricing Changes. Commencing on the Amendment Effective
Date, for all General Revolving Loans (other than General Revolving Loans that
are December Bridge Loans) then or thereafter outstanding, and until changed in
accordance with the applicable provisions of section 2.7(h) of the Credit
Agreement, based on the consolidated financial statements of the Borrower for a
fiscal quarter ended on or nearest to December 31, 2000 or thereafter, the
Applicable Eurodollar Margin for General Revolving Loans will be 250 basis
points and the Applicable Prime Rate Margin for General Revolving Loans will be
100 basis points.

(a) Commencing on the Amendment Effective Date, and until changed in accordance
with the applicable provisions of section 4.1(a) of the Credit Agreement, based
on the consolidated financial

<PAGE>

statements of the Borrower for a fiscal quarter ended on or nearest to December
31, 2000 or thereafter, the Applicable Commitment Fee Rate will be 50 basis
points per annum.

1.1. AV Associates Acquisitions. As contemplated by the definition of "Permitted
Acquisition" contained in section 1.1 of the Credit Agreement, the Lenders
hereby consent to the Acquisition by the Borrower of AV Associates, Inc., a
Connecticut corporation (the "AV Associates Acquisition"), on the terms
generally described in the descriptive materials previously furnished to the
Lenders by the Borrower.

1.1. Intellisys Acquisition. (a) The Lenders hereby consent to (1) the creation
of West Lake Acquisition Corporation, a Maryland corporation, Agoura Hills
Corporation, a Maryland corporation, MCSi-IG-HE, Inc., a Texas corporation,
MCSi-IG-PI, Inc., a Washington corporation, and MCSi-IG-PU, Inc., a Texas
corporation (together with any Subsidiary of each such company, collectively,
the "MCSi/Intellisys Subsidiaries" and, individually each an "MCSi/Intellisys
Subsidiary"), and (2) as contemplated by the definition of "Permitted
Acquisition" contained in section 1.1 of the Credit Agreement, the Acquisition
by the MCSi/Intellisys Subsidiaries of substantially all of the assets of
Intellisys Group, Inc., a Delaware corporation (the "Intellisys Acquisition"),
on the terms generally described in the descriptive materials previously
furnished to the Lenders by the Borrower; provided that such consent is
expressly conditioned on the following:

            (i) the aggregate amount of the consideration to be paid in
      connection with the Intellisys Acquisition (including, but not limited to,
      the assumption or incurring of liabilities, whether direct or contingent)
      shall not exceed $20,500,000, and such consideration shall not be borrowed
      under the Credit Agreement;

            (ii) notwithstanding anything in the Credit Agreement or any other
      Credit Document to the contrary, the Borrower shall not, and will not
      permit any of its Subsidiaries, to, directly or indirectly, (A) lend money
      or credit or make advances to any MCSi/Intellisys Subsidiary (except as
      expressly permitted pursuant to Section 9.4 of the Credit Agreement, as
      amended by this Amendment), (B) purchase or acquire any stock, obligations
      or securities of, or any other interest in, or make any capital
      contribution to, or other investment in, any MCSi/Intellisys Subsidiary
      (other than the holding of the outstanding shares of stock of the
      MCSi/Intellisys Subsidiaries by the Borrower and the initial
      capitalization thereof), (C) be or become a party to any joint venture or
      partnership with any MCSi/Intellisys Subsidiary, or (D) be or become
      obligated under any Guaranty Obligations with respect to any
      MCSi/Intellisys Subsidiary;

            (iii) notwithstanding anything in the Credit Agreement or any other
      Credit Document to the contrary, the Borrower will not, and will not
      permit any Subsidiary to, (A) enter into any transaction of merger or
      consolidation with any MCSi/Intellisys Subsidiary (whether or not the
      Borrower or such Subsidiary is the surviving entity), (B) sell or
      otherwise dispose of any of its property or assets to any MCSi/Intellisys
      Subsidiary other than in the ordinary course of business, or (C) agree to
      do any of the foregoing, directly or indirectly, at any future time;

            (iv) the Borrower shall not request that a Letter of Credit be
      issued at any time for the account or for the benefit of any
      MCSi/Intellisys Subsidiary;

            (v) no Intellisys Subsidiary shall be or become a party to any
      Designated Hedge Agreement; and

            (vi) the annual and quarterly financial statements of the Borrower
      and its Subsidiaries delivered to Administrative Agent and the Lenders
      pursuant to sections 8.1(a) and (b) of the Credit Agreement, and any other
      financial information of the Borrower and its Subsidiaries delivered at
      any time to Administrative Agent or any Lender, shall be prepared on a
      consolidated, and on consolidating basis and a consolidated basis,
      excluding the MCSi/Intellisys Subsidiaries, each to be in form and
      substance satisfactory to Administrative Agent or such Lender.

<PAGE>

      (b) So long as the Borrower and each of its Subsidiaries complies with the
conditions set forth in subsection (a) above, Administrative Agent and the
Lenders agree that, notwithstanding anything in the Credit Agreement or any
other Credit Document to the contrary, the MCSi/Intellisys Subsidiaries shall
not be deemed to be Subsidiaries of the Borrower for purposes of subpart (1) of
the definition of "Permitted Acquisition" or sections 8.10, 8.11, 9.5, 9.7, 9.8,
9.9, 9.10, 9.11, 9.14 or 9.15 of the Credit Agreement.

1.1. Limitation on Acquisitions. So long as any December Bridge Loan (or any
unpaid interest or fees thereon) is outstanding, the Borrower will not, and will
not permit any Subsidiary to, directly or indirectly make (a) any Acquisitions
(other than those expressly permitted pursuant to section 1.4 or 1.5 of this
Amendment), or (b) any public announcement of the intention of the Borrower or
any Subsidiary to make any Acquisition or of the shareholder or board of
directors approval of any Acquisition or proposed Acquisition.

1.1. Definition of "Permitted Acquisition." The definition of "Permitted
Acquisition" contained in section 1.1 of the Credit Agreement is amended to
replace subpart (1) thereof with the following:

                        (1) the pro forma ratio of

                                    (x) the Consolidated Total Debt of the
                  Borrower and the Indebtedness which is to be incurred to
                  acquire, or which is being directly or indirectly assumed in
                  connection with the acquisition of, such acquired business, on
                  a combined basis, to

                                    (y) the Borrower's Consolidated EBITDA and
                  the earnings before interest, taxes, depreciation and
                  amortization of the acquired business, on a combined basis
                  (but without giving effect to any credit for unobtained or
                  unrealized gains or any adjustments to overhead in connection
                  with such acquisition), as determined on an annualized basis
                  using a Testing Period consisting of the current fiscal year
                  to date through the most recent fiscal quarter or fiscal month
                  for which financial information is available and has been
                  delivered to the Lenders (or for a Testing Period consisting
                  of the previous fiscal year, if no financial information is
                  then available for the current fiscal year),

            is not greater than 3.50 to 1.00 (or 2.75 to 1.00, in the case of
            any Permitted Acquisition to be made after the acquisition of AV
            Associates, Inc.), such ratio being determined on a pro forma basis,
            as if such acquisition had been completed at the beginning of such
            Testing Period, and any such Indebtedness had been outstanding for
            such Testing Period; and

(a) Dividends, etc. Notwithstanding anything in the section 9.6 of the Credit
Agreement or elsewhere to the contrary, so long as any December Bridge Loan (or
any unpaid interest or fees thereon) is outstanding, the Borrower will not
directly or indirectly declare, order, pay or make any dividend (other than
dividends payable solely in capital stock of the Borrower) or other distribution
on or in respect of any capital stock of any class of the Borrower, whether by
reduction of capital or otherwise, or directly or indirectly make, or permit any
of its Subsidiaries to directly or indirectly make, any purchase, redemption,
retirement or other acquisition of any capital stock of any class of the
Borrower (other than for a consideration consisting solely of capital stock of
the same class of the Borrower) or any other Person or of any warrants, rights
or options to acquire or any securities convertible into or exchangeable for any
capital stock of the Borrower or any other Person.

1.1. Consolidated Total Debt/Consolidated EBITDA Ratio. Section 9.7 of the
Credit Agreement is amended to read in its entirety as follows:

            9.7. Consolidated Total Debt/Consolidated EBITDA Ratio. The Borrower
      will not at any time permit the ratio of (a) the amount of Consolidated
      Total Debt at such time to (b) Consolidated EBITDA for the Testing Period
      most recently ended, to exceed (i) 4.30 to 1.00 in the case of any Testing
      Period ended on or prior to June 29, 2000, (ii) 4.00 to 1.00, in the case
      of the Testing Periods ended June 30, 2000 and September 30, 2000, (iii)
      3.75 to 1.00, in the case of the Testing

<PAGE>

      Period ended December 31, 2000, and (iv) 3.00 to 1.00, in the case of any
      Testing Period ended thereafter.

1.1. Fixed Charge Coverage Ratio. Section 9.8 of the Credit Agreement is
amended, retroactively effective to September 30, 2000, to read in its entirety
as follows:

            9.8. Fixed Charge Coverage Ratio. The Borrower will not permit its
      Fixed Charge Coverage Ratio to be less than (a) 1.20 to 1.00 for any
      Testing Period ended on or prior to June 30, 2000, (b) 1.25 to 1.00, for
      the Testing Periods ended September 30, 2000, December 31, 2000 and March
      31, 2001, (c) 1.30 to 1.00 for the Testing Periods ended June 30, 2001 and
      September 30, 2001, and (d) 1.40 to 1.00 for the Testing Periods ended
      December 31, 2001 and thereafter.

1.1. Consolidated Capital Expenditures. Section 9.9 of the Credit Agreement is
amended, retroactively effective to September 30, 2000, to read in its entirety
as follows:

            9.9. Capital Expenditures. The Borrower will not, and will not
      permit any of its Subsidiaries to, make or incur Consolidated Capital
      Expenditures during any fiscal year (a) in excess of $10,500,000, in the
      case of the fiscal year ended December 31, 1999, (b) in excess of
      $11,000,000, in the case of the fiscal year ended December 31, 2000, or
      (iii) in excess of $5,000,000, in the case of any subsequent fiscal year.
      In the event actual Consolidated Capital Expenditures for any fiscal year
      are less than such amount, the excess amount may not be carried over to
      any subsequent period.

1.1. Minimum Consolidated Net Worth. Section 9.11 of the Credit Agreement is
amended, retroactively effective to September 30, 2000, to read in its entirety
as follows:

(i) 9.11. Minimum Consolidated Net Worth. The Borrower will not permit its
Consolidated Net Worth at any time to be less than (a) the minimum amounts
determined in accordance with the Credit Agreement prior to giving effect to
Amendment No. 11 to Amended and Restated Credit Agreement, dated as of December
8, 2000, for any time period prior to September 29, 2000, and (b) $130,000,000,
on September 30, 2000 and thereafter, except that effective as of the end of the
Borrower's fiscal quarter ended December 31, 2000, and as of the end of each
fiscal quarter thereafter, the foregoing amount (as it may from time to time be
increased as herein provided), shall be increased by 50% of the Consolidated Net
Income of the Borrower and its Subsidiaries for the fiscal quarter ended on such
date (there being no reduction in the case of any such Consolidated Net Income
which reflects a deficit), the foregoing amount (as it may from time to time be
increased as herein provided), shall be increased by an amount equal to 90% of
the cash proceeds (net of underwriting discounts and commissions and other
customary fees and costs associated therewith) from any sale or issuance of
equity by the Borrower after September 30, 2000 (other than any sale or issuance
to management or employees pursuant to employee benefit plans of general
application), and the foregoing amount (as it may from time to time be increased
as herein provided), shall be increased by an amount equal to 90% of the
increase in Consolidated Net Worth attributable to the issuance of common stock
or other equity interests subsequent to September 30, 2000 as consideration in
any Permitted Acquisitions.

1.1. Liens Covenant. Effective on the Amendment Effective Date, section 9.3 of
the Credit Agreement is amended to add the following new subsection (e) thereto
as follows:

            (e) Liens on assets, properties and rights of West Lake Acquisition
      Corporation, a Maryland corporation, Agoura Hills Corporation, a Maryland
      corporation, MCSi-IG-HE, Inc., a Texas corporation, MCSi-IG-PI, Inc., a
      Washington corporation, and MCSi-IG-PU, Inc., a Texas corporation
      (together with any Subsidiary of each such company, collectively, the
      "MCSi/Intellisys Subsidiaries" and, individually each an "MCSi/Intellisys
      Subsidiary"), securing Indebtedness permitted by section 9.4(j).

1.1. Indebtedness Covenant. Effective on the Amendment Effective Date, section
9.4 of the Credit Agreement is amended to add the following new subsections (i)
and (j) thereto as follows:

<PAGE>

            (i) loans or advances by the Borrower to any MCSi/Intellisys
      Subsidiary so long as the aggregate outstanding amount of all such loans
      and advances by the Borrower to all of the MCSi/Intellisys Subsidiaries
      does not exceed $2,500,000 at any time;

            (j) in addition to the loans or advances permitted pursuant to
      subsection (i) above, Indebtedness incurred by the MCSi/Intellisys
      Subsidiaries to any Person (other than the Borrower or any its
      Subsidiaries, but specifically including any credit facility that may be
      provided by PNC Bank, National Association, or any affiliate thereof or
      any other Lender, in its sole discretion, independent of this Agreement)
      provided that the aggregate outstanding principal amount of such
      Indebtedness outstanding at any time shall not exceed $25,000,000 at any
      time.

1.1. Pledge of Zengine Shares. Pursuant to the terms and conditions of the
Pledge Agreement, the Borrower shall, on or prior to the Amendment Effective
Date, (a) deliver to the Collateral Agent, as security for the Obligations, all
of the share certificates of Zengine, Inc. owned by the Borrower, together with
appropriate undated stock powers undated and executed in blank, or, if the
Borrower's equity interest in Zengine, Inc. is not evidenced by share
certificates take such action as the Collateral Agent deems necessary or
appropriate to provide to the Collateral Agent a pledge of and lien on such
equity interest, and (b) take such other action as the Collateral Agent deems
necessary or appropriate in connection with the foregoing.

1.1. Amendment Fee. As consideration for the changes in the Credit Agreement
pursuant to this Amendment, the Borrower will (a) pay to the Administrative
Agent, for pro rata distribution among those Lenders that increase their
respective General Revolving Commitments in accordance with the amounts by which
such respective General Revolving Commitments are temporarily increased as
provided in section 1.1(a) above, an increase fee at the rate of 100 basis
points, calculated on the $25,000,000 aggregate amount of the temporary
increase, and (b) pay to the Administrative Agent, for pro rata distribution
among those Lenders that increase their respective General Revolving Commitments
in accordance with the amount of such respective General Revolving Commitments
as in effect immediately prior to giving effect to the temporary increase
provided for in section 1.1(a) above, an amendment fee at the rate of 12.50
basis points, calculated on $160,000,000. The foregoing fees shall be payable in
immediately available funds on the Amendment Effective Date.

1. REPRESENTATIONS AND WARRANTIES.

      The Borrower represents and warrants to the Lenders and the Administrative
Agent as follows:

1.1. Authorization, Validity and Binding Effect. This Amendment has been duly
authorized by all necessary corporate action on the part of the Borrower, has
been duly executed and delivered by a duly authorized officer or officers of the
Borrower, and constitutes the valid and binding agreement of the Borrower,
enforceable against the Borrower in accordance with its terms.

1.1. Representations and Warranties True and Correct. The representations and
warranties of the Borrower contained in the Credit Agreement, as amended hereby,
are true and correct on and as of the date hereof as though made on and as of
the date hereof, except to the extent that such representations and warranties
expressly relate to a specified date, in which case such representations and
warranties are hereby reaffirmed as true and correct when made.

1.1. No Event of Default, etc. No condition or event has occurred or exists
which constitutes or which, after notice or lapse of time or both, would
constitute an Event of Default.

1.1. Compliance. The Borrower is in full compliance with all covenants and
agreements contained in the Credit Agreement, as amended hereby.

1.1. Recent Financial Statements. The Borrower has furnished to the Lenders and
the Administrative Agent complete and correct copies of the unaudited condensed
consolidated balance sheet of

<PAGE>

the Borrower and its consolidated subsidiaries as of September 30, 2000, and the
related unaudited condensed consolidated statements of income and of cash flows
of the Borrower and its consolidated subsidiaries for the fiscal period then
ended, as contained in the Form 10-Q Quarterly Report of the Borrower filed with
the SEC. All such financial statements have been prepared in accordance with
GAAP, consistently applied (except as stated therein), and fairly present the
financial position of the Borrower and its consolidated subsidiaries as of the
date indicated and the consolidated results of their operations and cash flows
for the period indicated, subject to normal audit adjustments, none of which
will involve a Material Adverse Effect.

1. EFFECTIVENESS.

This Amendment shall become effective on (the "Amendment Effective Date")
December 8, 2000, subject to the satisfaction of the following conditions on or
before such date:

(a) this Amendment shall have been executed by the Borrower and the
Administrative Agent, and counterparts hereof as so executed shall have been
delivered to the Administrative Agent;

(a) the Acknowledgment and Consent appended hereto shall have been executed by
the Credit Parties named therein, and counterparts hereof as so executed shall
have been delivered to the Administrative Agent;

(a) the Administrative Agent shall have been notified by all of the Lenders that
such Lenders have executed this Amendment (which notification may be by
facsimile or other written confirmation of such execution);

(a) the Borrower shall have duly executed and delivered to the Administrative
Agent, for the account of the Lenders, additional General Revolving Notes made
payable to the order of the respective Lenders in the amount of the temporary
increase in their respective General Revolving Commitments provided for in this
Amendment, and otherwise conforming to the requirements of the Credit Agreement;

(a) the Borrower shall have delivered to the Administrative Agent a certificate
of its Secretary or an Assistant Secretary, dated as of a recent date,
certifying the due adoption by the Board of Directors of a resolution or
resolutions approving the increase in the Total General Revolving Commitment
under the Credit Agreement to $181,000,000 and the other modifications to the
Credit Agreement set forth in this Amendment, and certifying that such
resolution(s) remains in full force and effect, and such certificate and
resolution(s) shall be satisfactory in form and substance to the Administrative
Agent;

(a) the Borrower shall have delivered to the Administrative Agent a list, as of
the date of this Amendment, of each Subsidiary of the Borrower and the direct or
indirect ownership of the Borrower therein; and

(a) the Borrower shall have paid to the Administrative Agent, for the account of
the Lenders, such amendment fees as are payable at such time as provided in
section 1.14 of this Amendment (the Administrative Agent hereby agreeing to
promptly re-transmit pro rata portions of the amendment fees to the respective
Lenders).

Subject to satisfaction of the foregoing conditions, the Administrative Agent
shall notify the Borrower and each Lender in writing of the effectiveness
hereof.

1. RATIFICATIONS.

      The terms and provisions set forth in this Amendment shall modify and
supersede all inconsistent terms and provisions set forth in the Credit
Agreement, and except as expressly modified and superseded by this Amendment,
the terms and provisions of the Credit Agreement are ratified and confirmed and
shall continue in full force and effect.
<PAGE>

1. MISCELLANEOUS.

1.1. Successors and Assigns. This Amendment shall be binding upon and inure to
the benefit of the Borrower, each Lender and the Administrative Agent and their
respective permitted successors and assigns.

1.1. Survival of Representations and Warranties. All representations and
warranties made in this Amendment shall survive the execution and delivery of
this Amendment, and no investigation by the Administrative Agent or any Lender
or any subsequent Loan or issuance of a Letter of Credit shall affect the
representations and warranties or the right of the Administrative Agent or any
Lender to rely upon them.

1.1. Reference to Credit Agreement. The Credit Agreement and any and all other
agreements, instruments or documentation now or hereafter executed and delivered
pursuant to the terms of the Credit Agreement as amended hereby, are hereby
amended so that any reference therein to the Credit Agreement shall mean a
reference to the Credit Agreement as amended hereby.

1.1. Expenses. As provided in the Credit Agreement, but without limiting any
terms or provisions thereof, the Borrower agrees to pay on demand all costs and
expenses incurred by the Administrative Agent in connection with the
preparation, negotiation, and execution of this Amendment, including without
limitation the costs and fees of the Administrative Agent's special legal
counsel, regardless of whether this Amendment becomes effective in accordance
with the terms hereof, and all costs and expenses incurred by the Administrative
Agent or any Lender in connection with the enforcement or preservation of any
rights under the Credit Agreement, as amended hereby.

1.1. Severability. Any term or provision of this Amendment held by a court of
competent jurisdiction to be invalid or unenforceable shall not impair or
invalidate the remainder of this Amendment and the effect thereof shall be
confined to the term or provision so held to be invalid or unenforceable.

1.1. Applicable Law. This Amendment shall be governed by and construed in
accordance with the laws of the State of Ohio.

1.1. Headings. The headings, captions and arrangements used in this Amendment
are for convenience only and shall not affect the interpretation of this
Amendment.

1.1. Entire Agreement. This Amendment is specifically limited to the matters
expressly set forth herein. This Amendment and all other instruments, agreements
and documentation executed and delivered in connection with this Amendment
embody the final, entire agreement among the parties hereto with respect to the
subject matter hereof and supersede any and all prior commitments, agreements,
representations and understandings, whether written or oral, relating to the
matters covered by this Amendment, and may not be contradicted or varied by
evidence of prior, contemporaneous or subsequent oral agreements or discussions
of the parties hereto. There are no oral agreements among the parties hereto
relating to the subject matter hereof or any other subject matter relating to
the Credit Agreement.

1.1. Counterparts. This Amendment may be executed by the parties hereto
separately in one or more counterparts, each of which when so executed shall be
deemed to be an original, but all of which when taken together shall constitute
one and the same agreement.

<PAGE>

      IN WITNESS WHEREOF, this Amendment has been duly executed and delivered as
of the date first above written.

<TABLE>
<S>                                              <C>
MCSi, Inc.,                                      PNC BANK, NATIONAL ASSOCIATION,
     a Maryland corporation which is the               individually as a Lender, a Letter of
     successor by merger to Miami Computer             Credit Issuer, the Swing Line Lender and as
     Supply Corporation, an Ohio corporation           Administrative Agent

By:_________________________________________     By:______________________________________________
           Title:                                           Vice President
NATIONAL CITY BANK,                              FIRSTAR BANK, N. A.
     individually as a Lender and
     as Documentation Agent

                                                 By:_______________________________________________
By:________________________________________                 Title:
           Title:
KEY CORPORATE CAPITAL INC.                       THE HUNTINGTON NATIONAL BANK



By:_________________________________________     By:______________________________________________
           Title:                                           Title:
BANK ONE, INDIANA, N. A.                         THE PROVIDENT BANK



By:_________________________________________     By:______________________________________________
           Title:                                           Title:
</TABLE>

<PAGE>

                           ACKNOWLEDGMENT AND CONSENT

            For the avoidance of doubt, and without limitation of the intent and
effect of sections 6 and 10 of the Amended and Restated Subsidiary Guaranty (as
such term is defined in the Credit Agreement referred to in the Amendment No. 11
to Amended and Restated Credit Agreement (the "Amendment"), to which this
Acknowledgment and Consent is appended), each of the undersigned hereby
unconditionally and irrevocably (i) acknowledges receipt of a copy of the Credit
Agreement and the Amendment, and (ii) consents to all of the terms and
provisions of the Credit Agreement as amended by the Amendment.

            Capitalized terms which are used herein without definition shall
have the respective meanings ascribed thereto in the Credit Agreement referred
to herein. This Acknowledgment and Consent is for the benefit of the Lenders and
the Administrative Agent, any other person who is a third party beneficiary of
the Subsidiary Guaranty, and their respective successors and assigns. No term or
provision of this Acknowledgment and Consent may be modified or otherwise
changed without the prior written consent of the Administrative Agent, given as
provided in the Credit Agreement. This Acknowledgment and Consent shall be
binding upon the successors and assigns of each of the undersigned. This
Acknowledgment and Consent may be executed by any of the undersigned in separate
counterparts, each of which shall be an original and all of which together shall
constitute one and the same instrument.

            IN WITNESS WHEREOF, each of the undersigned has duly executed and
delivered this Acknowledgment and Consent as of the date of the Amendment
referred to herein.

Diversified Data Products, Inc.                Electronic Image Systems, Inc.
Computer Showcase, Inc.                        Consolidated Media Systems, Inc.
Jack Kelly & Associates, Inc.                  Technical Industries, Inc.
Dreher Business Products Corporation           C&G Marketing, Inc.
Central Audio Video, Inc.                      Fairview-AFX, Inc.
Audio-Visual Systems, Inc.                     Video Images, Inc.
Midwest Visual Equipment Co., Inc.
Westek Presentation Systems, Inc.
                                               By:______________________________
                                                      Ira Stanley, an officer
By:__________________________________
        Michael E. Peppel, an officer