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                                                                   EXHIBIT 10.58

 
                                PROMISSORY NOTE
                                        
                                                   Dated:  February 15, 1999

Principal Amount:  $53,362.32                           State of Colorado

     FOR VALUE RECEIVED, the undersigned hereby jointly and severally promise to
pay to the order of Matrix Capital Corporation.

The sum of Fifty-three Thousand, Three Hundred and Sixty-two and 32/100, Dollars
($53,362.32), together with interest thereon at the rate of Prime per annum on
the unpaid balance. Said sum shall be paid in the manner following:

     All principal and interest shall be due on February 15, 2000.

     All payment shall be first applied to interest and the balance to
principal. This note may be prepaid, at any time, in whole or in part, without
penalty. All prepayments shall be applied in reverse order of maturity.

     This note shall at the option of any holder hereof be immediately due and
payable upon the failure to make any payment due hereunder within   N/A   days
of its due date.

     This note at the option of any holder hereof may be extended on an annual
basis for increments of one (1) year. The terms and interest rate will remain
constant.

     In the event this note shall be in default, and placed with an attorney for
collection, then the undersigned agree to pay all reasonable attorney's fees and
costs of collection. Payments not made within five (5) days of due date shall be
subject to a late charge of 2% of said payment. All payments hereunder shall be
made to such address as may from time to time be designed by any holder hereof.

     The undersigned and all other parties to this note, whether as endorsers,
guarantors or sureties, agree to remain fully bound hereunder until this note
shall be fully paid and waive demand, presentment and protest and all notices
thereto and further agree to remain bound, notwithstanding any extension,
renewal, modification, waiver, or other indulgence by any holder or upon the
discharge or release of any obligor hereunder to this note, or upon the
exchange, substitution, or release of any collateral granted as security for
this note. No modification or indulgence by any holder hereof shall be binding
unless in writing: and any indulgence on any one occasion shall not be an
indulgence for any other or future occasion. Any modification or change of
terms, hereunder granted by any holder hereof, shall be valid and binding upon
each of the undersigned, notwithstanding the acknowledgment of any of the
undersigned, and each of the undersigned does hereby irrevocably grant to each
of the others a power of attorney to enter into any such modification on their
behalf. The rights of any holder hereof shall be cumulative and not necessarily
successive. This note shall take effect as sealed instrument and shall be
construed, governed and enforced in accordance with the laws of the State first
appearing at the head of this note. The undersigned hereby execute this note as
principals and not as sureties.

Maker:

                /s/
-----------------------------------
Thomas P. Cronin