<PAGE>
 
                                                              EXHIBIT 3(i)


                        CERTIFICATE OF INCORPORATION OF
                       LEGACY SOFTWARE ACQUISITION, INC.
                             A DELAWARE CORPORATION

                                   ARTICLE I

     The name of this corporation is Legacy Software Acquisition, Inc.

                                   ARTICLE II

  The address of the registered office of the corporation in the State of
Delaware is 1209 Orange Street, in the City of Wilmington, County of New Castle.
The name of its registered agent at such address is the Corporation Trust
Company.

                                  ARTICLE III

     The nature of the business or purposes to be conducted or promoted is to
engage in any lawful act or activity for which corporations may be organized
under the General Corporation Law of Delaware.

                                   ARTICLE IV

     (A) This corporation is authorized to issue two classes of shares to be
         designated respectively preferred stock ("preferred stock") and common
         stock ("common stock"). The total number of shares of capital stock
         that the corporation is authorized to issue is fifteen million
         (15,000,000). The total number of shares of preferred stock this
         corporation shall have authority to issue is five million (5,000,000).
         The total number of shares of common stock this corporation shall have
         authority to issue is ten million (10,000,000). The preferred stock
         shall have par value $.001 Per share and the common stock shall have
         par value $.001 Per share.

                                     F-25


<PAGE>
 
     (B) The shares of preferred stock may be issued from time to time in
     one or more series. The board of directors of the corporation (the
     "Board of Directors") is expressly authorized to provide for the issue
     of all or any of the shares of the preferred stock in one or more
     series, and to fix the number of shares and to determine or alter, for
     each such series, such voting powers, full or limited, or no voting
     powers, and such designations, preferences, an relative, participating,
     optional, or other rights and such qualifications, limitations, or
     restrictions thereof, as shall be stated and expressed in the
     resolution or resolutions adopted by the board of directors providing
     for the issue of such shares (a "preferred stock designation") and as
     may be permitted by the general corporation law of the State of
     Delaware. The Board of Directors is also expressly authorized to
     increase or decrease (but not below the number of shares of such series
     then outstanding) the number of shares of any series subsequent to the
     issue of shares of that series. In case the number of shares of any
     such series shall be so decreased, the shares constituting such
     decrease shall resume the status that they had prior to adoption of the
     resolution originally fixing the number of shares of such series.

                                   ARTICLE V

     The name and mailing address of the incorporator is Ariella J. Lehrer, 5340
Alla Road, Los Angeles, CA 90066.

                                   ARTICLE VI

     Except as otherwise provided in this Certificate of Incorporation, in
furtherance and not in limitation of the powers conferred by statue, the board
of directors is expressly authorized to make, repeal, alter, amend and rescind
any or all of the Bylaws of the corporation.


                                     F-26


<PAGE>
 
                                  ARTICLE VII

     The number of directors of the corporation shall be fixed from time to time
by, or in a manner provided in, the bylaws or amendment thereof duly adopted by
the Board of Directors or by the stockholders.

                                  ARTICLE VIII

     Elections of directors need not be by written ballot unless the bylaws of
the corporation shall so provide.

                                   ARTICLE IX

     Meetings of stockholders may be held within or without the State of
Delaware, as the Bylaws may provide. The books of the corporation may be kept
(subject to any provision contained in the statutes) outside the State of
Delaware at such place or places as may be designated from time to time by the
Board of Directors or in the Bylaws of the corporation.

                                   ARTICLE X

     A director of the corporation shall not be personally liable to the
corporation or its stockholders for monetary damages for breach of fiduciary
duty as a director, except for liability (i) for any breach of the director's
duty of loyalty to the corporation or its stockholders, (ii) for acts or
omissions not in good faith or which involve intentional misconduct or a knowing
violation of law, (iii) under section 174 of the Delaware General Corporation
Law, or (iv) for any transaction from which the director derived any improper
personal benefit. If the Delaware General Corporation Law is amended after
approval by the stockholders of this article to authorize corporate action
further eliminating or limiting the personal liability of directors then the
liability of a director of the corporation shall be eliminated or limited to the
fullest extent permitted by the Delaware General Corporation Law as amended.

                                     F-27


<PAGE>
 
     Any repeal or modification of the foregoing provision of this article x by
the stockholders of the corporation shall not adversely affect any right or
protection of a director of the corporation existing at the time of such repeal
or modification.

                                   ARTICLE XI

     The corporation reserves the right to amend, alter, change or repeal any
provision contained in this Certificate of Incorporation, in the manner now or
hereafter prescribed by statue, and all rights conferred upon stockholders
herein are granted subject to this reservation.

     IN WITNESS WHEREOF, The undersigned has signed this certificate this 20th
day of December, 1995



              /S/ ARIELLA J. LEHRER
              ---------------------

              Ariella J. Lehrer, Incorporator

                                     F-28