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                                                                   EXHIBIT 10.20

                                 PROMISSORY NOTE


$451,503.94                                                   September 30, 1999


         FOR VALUE RECEIVED, the undersigned, Citadel Technology, Inc., a
Delaware corporation (the "Maker"), promises to pay to the order of How2HQ.com,
Inc. (the "Payee"), at such place as Payee may designate in writing, in lawful
money of the United States of America, the principal sum of Four Hundred Fifty
One Thousand Five Hundred Three Dollars and Ninety Four Cents ($451,503.94) on
the terms and conditions hereinafter set forth.

         This Note shall bear interest at a rate of 5% per year (simple
interest) and shall mature upon demand by the Payee, at which time all
outstanding principal and interest shall be due and payable. Maker shall have
the right to prepay this Note, in whole or in part, at any time without penalty.
Maker's payment of this Note shall be secured by the pledge of 300,000 shares of
common stock of How2HQ.com, Inc.

          The entire unpaid principal balance of this Note shall immediately
become due and payable, at the option of Payee, upon the occurrence of the
following event of default (the "Event of Default"): Failure by Maker to pay any
installment of principal hereof as and when the same becomes due and payable in
accordance with the terms hereof and the continuation of said failure for a
period of ten (10) days after Payee has provided Maker with written notice of
such failure. In the event an Event of Default specified hereinabove shall
occur, Payee may proceed to protect and enforce its rights either by suit in
equity and/or by action at law, by other appropriate proceedings or by
converting the pledged shares from Maker's ownership to Payee's ownership. No
delay on the part of Payee in the exercise of any power or right under this
Note, or under any other instrument executed pursuant thereto shall operate as a
waiver thereof, nor shall a single or partial exercise of any other power or
right preclude further exercise thereof.

         It is hereby specially agreed that if this Note is placed into the
hands of an attorney for collection, or if proved, established, or collected in
any court, Maker agrees to pay to Payee an amount equal to all expenses incurred
in enforcing or collecting this Note, including court costs and reasonable
attorneys' fees.

         Except for the notice expressly provided herein, the undersigned and
all endorsers, sureties, and guarantors hereof hereby jointly and severally
waive presentment for payment, demand, notice of nonpayment, protest, notice of
protest, and without further notice hereby consent to renewals, extensions, or
partial payments either before or after maturity.

         All agreements between Maker and Payee, whether now existing or
hereafter arising and whether written or oral, are expressly limited so that in
no contingency or event whatsoever shall the amount paid, or agreed to be paid,
to Payee hereof for the use, forbearance, or detention of the money advanced to
Maker, or for the performance or payment of any covenant or obligation


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contained herein, exceed the maximum amount permissible under applicable federal
or state law. If, from any circumstance whatsoever, fulfillment of any provision
hereof at the time performance of such provision shall be due shall involve
transcending the limit of validity prescribed by law, then the obligation to be
fulfilled shall be reduced to the limit of such validity, and if from any such
circumstance Payee shall ever receive as interest under this Note or otherwise
an amount that would exceed the highest lawful rate, such amount that would be
excessive interest shall be applied to the reduction of the principal amount
owing under this Note and not to the payment of interest or, if such excessive
interest exceeds the unpaid principal balance of this Note, such excess shall be
refunded to Maker. All sums paid or agreed to be paid to Payee for the use,
forbearance, or detention of the indebtedness evidenced hereby shall, to the
extent permitted by applicable law, be amortized, prorated, allocated, and
spread throughout the full term of such indebtedness until payment in full so
that the actual rate of interest on account of such indebtedness is uniform
throughout the term thereof. The terms and provisions of this paragraph shall
control every other provision of all agreements between Maker and Payee.

         This Note shall be governed by and construed in accordance with the
laws of the State of Texas and the laws of the United States applicable to
transactions in Texas.

MAKER:

CITADEL TECHNOLOGY, INC.



By:
   ---------------------------------------
   Steven B. Solomon, Its CEO


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