<PAGE>   1
                UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                 AMENDMENT NO. 1
                                       TO
                                   FORM 10-K/A

(Mark One)        [X]      Annual report pursuant to Section 13 or 15(d) of the
                           Securities Exchange Act of 1934 for the fiscal year
                           ended December 31, 1999

                  [ ]      Transition report pursuant to Section 13 or 15(d) of
                           the Securities Exchange Act of 1934 For the
                           transition period from ____________to________________

                         Commission File Number 0-21209
                                 AHT CORPORATION
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

Delaware                                           13-3893841
(STATE OR OTHER JURISDICTION                       (IRS EMPLOYER IDENTIFICATION
OF INCORPORATION OR ORGANIZATION)                   NUMBER)

555 White Plains Road, Tarrytown, New York          10591
(ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)            (ZIP CODE)

(914) 524-4200
(REGISTRANTS' TELEPHONE NUMBER, INCLUDING AREA CODE)

         Securities registered pursuant to Section 12(b) of the Act: None

         Securities registered pursuant to Section 12(g) of the Act: Common
Stock, $.01 par value

INDICATE BY CHECK MARK WHETHER THE REGISTRANT: (1) HAS FILED ALL REPORTS
REQUIRED TO BE FILED BY SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF
1934 DURING THE PRECEDING 12 MONTHS (OR FOR SUCH SHORTER PERIOD THAT THE
REGISTRANT WAS REQUIRED TO FILE SUCH REPORTS), AND (2) HAS BEEN SUBJECT TO SUCH
FILING REQUIREMENTS FOR THE PAST 90 DAYS.
                                                                  YES [X] NO [ ]

INDICATE BY CHECK MARK IF DISCLOSURE OF DELINQUENT FILERS PURSUANT TO ITEM 405
OF REGULATION S-K IS NOT CONTAINED HEREIN, AND WILL NOT BE CONTAINED, TO THE
BEST OF REGISTRANT'S KNOWLEDGE, IN DEFINITIVE PROXY OR INFORMATION STATEMENTS
INCORPORATED BY REFERENCE IN PART III OF THIS FORM 10-K OR ANY AMENDMENT TO THIS
FORM 10-K: [X]

<PAGE>   2

THE AGGREGATE MARKET VALUE OF THE SHARES OF COMMON STOCK HELD BY NON-AFFILIATES
OF THE REGISTRANT IS $52,965,758, BASED ON THE CLOSING PRICE OF THE COMMON STOCK
ON MARCH 24, 2000. AS OF MARCH 24, 2000, THERE WERE 11,123,366 SHARES OF COMMON
STOCK OUTSTANDING.

                       DOCUMENTS INCORPORATED BY REFERENCE

                                      None

STATEMENTS MADE OR INCORPORATED INTO THIS ANNUAL REPORT INCLUDE A NUMBER OF
FORWARD-LOOKING STATEMENTS WITHIN THE MEANING OF SECTION 27A OF THE SECURITIES
ACT OF 1933, AS AMENDED, AND SECTION 21E OF THE SECURITIES EXCHANGE ACT OF 1934.
FORWARD-LOOKING STATEMENTS INCLUDE, WITHOUT LIMITATION, STATEMENTS CONTAINING
THE WORDS "ANTICIPATES," "BELIEVES," "EXPECTS," "INTENDS," "FUTURE" AND WORDS OF
SIMILAR IMPORT WHICH EXPRESS MANAGEMENT'S BELIEF, EXPECTATIONS OR INTENT
REGARDING THE COMPANY'S FUTURE PERFORMANCE. THE COMPANY'S ACTUAL RESULTS COULD
DIFFER MATERIALLY FROM THOSE SET FORTH IN THE FORWARD-LOOKING STATEMENTS.
FORWARD-LOOKING STATEMENTS, INCLUDING STATEMENTS AS TO INDUSTRY TRENDS, FUTURE
ECONOMIC PERFORMANCE, ANTICIPATED PROFITABILITY, ANTICIPATED REVENUES AND
EXPENSES, AND PRODUCTS OR SERVICE LINE GROWTH MAY BE SIGNIFICANTLY IMPACTED BY
CERTAIN RISKS AND UNCERTAINTIES, INCLUDING, BUT NOT LIMITED TO, FAILURE OF THE
CLINICAL E-COMMERCE INDUSTRY TO DEVELOP AT ANTICIPATED RATES, FAILURE OF THE
COMPANY'S CLINICAL INFORMATION TECHNOLOGY PRODUCTS AND SERVICES TO GAIN
SIGNIFICANT MARKET ACCEPTANCE, FAILURE TO MEET OPERATING OBJECTIVES OR TO
EXECUTE THE OPERATING PLAN, FAILURE TO SUCCESSFULLY RESTRUCTURE AHT'S BUSINESS
UNITS, COMPETITION AND OTHER ECONOMIC FACTORS. NO ASSURANCES CAN BE GIVEN AS TO
THE OUTCOME OF ANY PENDING LAWSUITS AGAINST ADVANCED HEALTH CORPORATION OR AHT
CORPORATION.

ITEM 11. EXECUTIVE COMPENSATION

The following table sets forth a summary of the compensation of the Company's
Chief Executive Officer and each other executive officer of the Company who
earned in excess of $100,000 in annual salary and bonus during the Company's
fiscal year ended December 31, 1999 (collectively, the "Named Executive
Officers"), for services rendered in all capacities to the Company during the
Company's fiscal years ended December 31, 1999, 1998, and 1997.



<PAGE>   3
                           SUMMARY COMPENSATION TABLE
                             Long-Term Compensation
                           Annual Compensation Awards

<TABLE>
<CAPTION>
                                                                                Securities Underlying
                                                                                Options/SARs

Name and Principal Position                                   Year              ($)Salary                 (#)
------------------------------------------------------------------------------------------------------------------
<S>                                                           <C>               <C>                       <C>
Jonathan Edelson, M.D, Chairman,                              1999              298,240                   200,000
Chief Executive Officer, and President                        1998              298,589                       ---
                                                              1997              269,224                   150,000

Robert J. Alger, Executive Vice President                     1999              181,219                    60,000
and Chief Information Officer                                 1998              178,431                    25,000
                                                              1997              169,261                    60,000

Jeffrey M. Sauerhoff                                          1999              185,519                    10,000
Chief Financial Officer                                       1998              172,902                    50,731
                                                              1997              130,319                    22,255

Eddy W. Friedfeld, Senior Vice President-                     1999              164,883                    22,000
Business & Legal Affairs, General Counsel                     1998              152,566                    55,000
and Secretary                                                 1997               52,333                    22,500
</TABLE>


                     OPTIONS/SAR GRANTS IN LAST FISCAL YEAR

<TABLE>
<CAPTION>
                                           Individual Grants                                               Potential Realizable
                                                                                                         Value At Assumed Annual
                                                                                                           Rates of Stock Price
                                                                                                         Appreciation for Option
                                                                                                                   Term
                                Number of        Percent of Total
                               Securities          Options/SARs
                               Underlying           Granted to
                              Options/ SARs        Employees in         Exercise or
                               Granted (#)          Fiscal Year          Base Price  Expiration
             Name                  (b)                  (c)               ($/Sh)        Date           5% ($)        10% (4)
             (a)                                                            (d)         (e)              (f)           (g)
<S>                              <C>                    <C>              <C>          <C>              <C>          <C>
Jonathan Edelson                 150,000                28.67%           $  1.810     01/08/09         $170,745     $ 432,701
Jonathan Edelson                  50,000                 9.56%              4.130     07/23/09         $129,867     $ 329,108
Robert J. Alger                   30,000                 5.73%              1.810     01/08/09         $ 34,149     $  86,540
Robert J. Alger                   30,000                 5.73%              4.130     07/23/09         $ 77,920     $ 197,465
Jeffrey M. Sauerhoff              10,000                 1.91%              4.130     07/23/09         $ 25,973     $  65,822
Eddy W. Friedfeld                 12,000                 2.29%              2.880     04/09/09         $ 21,735     $  55,080
Eddy W. Friedfeld                 10,000                 1.91%              4.130     07/23/09         $ 38,473     $  78,322
</TABLE>


The following table sets forth certain information regarding options held at
December 31, 1999, by each of the Named Executive Officers.

<PAGE>   4

AGGREGATED OPTION/SAR EXERCISES IN LAST FISCAL YEAR AND FISCAL YEAR END
OPTION/SAR VALUES


<TABLE>
<CAPTION>
Number of Securities Underlying                                 Value of Unexercised In-the-Money
Unexercised Options at Fiscal Year-End                                 Options at Fiscal Year-End (1)
--------------------------------------------------              -------------------------------------------

                            Exercisable        Unexercisable           Exercisable    Unexercisable
<S>                           <C>                <C>                   <C>              <C>
Jonathan Edelson, M.D.        151,735            247,917               $   299,529      $565,187
Robert J. Alger                61,522             93,854                   136,402       193,156
Jeffrey M. Sauerhoff           45,336             50,969                   113,261       126,706
Eddy W. Friedfeld              33,958             65,542                    91,602       157,253
</TABLE>

(1)      Value of unexercised in-the-money options is based on a value of $4.69
         per share of the Company's Common Stock, the fair value of the
         Company's Common Stock on December 31, 1999. Amounts reflected are
         based on the assumed value minus the exercise price multiplied by the
         number of shares subject to the option.


ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT The
following table sets forth certain information regarding the ownership of Common
Stock as of May 1, 2000 with respect to (i) each person known by the Company to
own beneficially more than 5% of the outstanding shares of Common Stock, (ii)
each of the Company's directors, (iii) certain executive officers of the Company
and (iv) all directors and officers as a group. Unless otherwise indicated, the
address for each stockholder is c/o the Company, 555 White Plains Road,
Tarrytown, New York 10591.

<TABLE>
<CAPTION>
                                                                                SHARES OF
                                                                                COMMON
NAME AND ADDRESS                                                                STOCK(1)               PERCENT(1)
-----------------------------------------------------------------------------------------------------------------
Cybear, Inc.(2)
<S>                                                                             <C>                       <C>
  407 E. Grand River, Brighton, MI 48116                                        2,008,670                 15.3%
Dimensional Fund Advisors
  1299 Ocean Avenue, 11th Floor, Santa Monica, CA 90401                           763,800                  6.9%
Tudor Investment Group et al.
  One Liberty Plaza, 51st Floor, New York, NY  10006                              640,964                  5.8%
Jonathan Edelson, MD (3)                                                          621,959                  5.6%
Robert J. Alger (4)                                                                86,761                   *
Jeffrey M. Sauerhoff (5)                                                           50,257                   *
Eddy W. Friedfeld (6)                                                              37,958                   *
James Carney (7)                                                                   27,083                   *
Barry Kurokawa (8)                                                                 29,090                   *
Arthur M. Southam, MD (9)                                                           3,333                   *

All directors and executive officers as a group (7 persons)(10)                   856,441                   7.7%
</TABLE>

*Represents less than 1% of the outstanding shares of Common Stock.

(1) Beneficial ownership is determined in accordance with the rules of the
Securities and Exchange Commission (the "Commission") and generally includes
voting or investment power with respect to securities and includes options
exercisable within 60 days of May 1, 2000. Except as indicated by footnote, and
subject to community property laws where applicable, the persons named in the
table above have sole voting and investment power with respect to all
<PAGE>   5
shares of Common Stock shown as beneficially owned by them. Percentage of
beneficial ownership is based on 11,130,449 shares of Common Stock outstanding
as of May 1, 2000 plus securities and options exercisable individually within 60
days of May 1, 2000.

(2) Assuming exercise of warrants and conversion of a note issued in connection
with the Cybear agreement.

(3) Includes currently exercisable options to purchase 226,735 shares of Common
Stock.

(4) Includes currently exercisable options to purchase 86,761 shares of Common
Stock.

(5) Includes currently exercisable options to purchase 50,257 shares of Common
Stock.

(6) Includes currently exercisable options to purchase 37,958 shares of Common
Stock.

(7) Includes currently exercisable options to purchase 27,083 shares of Common
Stock.

(8) Includes currently exercisable options to purchase 27,090 shares of Common
Stock.

(9) Includes currently exercisable options to purchase 3,333 shares of Common
Stock.

(10) See notes (3), (4), (5), (6), (7), (8) and (9).


ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

         In 1997, 1998 and 1999, in accordance with the Company's Senior
Executive Loan Policy, which is administered by the Compensation Committee of
the Board of Directors, the Company made loans in the aggregate amounts of
$800,000 and $145,000 to each of Dr. Edelson, and Mr. Alger, respectively. These
loans are due three years from the loan date with interest payable monthly at a
rate of 6% per annum. As of May 31, 2000, the loans outstanding including
interest and net of payments were $576,000 and $168,000 for Dr. Edelson and Mr.
Alger, respectively. Dr. Edelson and Mr. Alger have agreed to repay such loans
no later than March 31, 2001. The Compensation Committee has agreed to extend
the term of payment for payment of certain loans to each of Dr. Edelson and Mr.
Alger to December 31, 2000.

         The Company believes that all of the transactions set forth above were
made on terms no less favorable to the Company than could have been obtained
from unaffiliated third parties. All transactions, including loans, between the
Company and its officers, directors and principal stockholders and their
affiliates are approved by a majority of the Board of Directors, including a
majority of the independent and disinterested outside directors of the Board of
Directors.

SIGNATURES

         Pursuant to the requirements of the Securities Exchange Act of 1934,
the Registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.


                                                 AHT CORPORATION

Date: June 19, 2000                              By:  /s/ Jeffrey M. Sauerhoff
                                                      ------------------------
                                                 Jeffrey M. Sauerhoff
                                                 Chief Financial Officer