SUBLEASE EXTENTION AGREEMENT


Allstar Systems, Inc.  ("Sublessee") and Allstar Equities,  Inc.  ("Sublessor"),
hereby, as of December 31, 1998, agree to extend that certain SUBLEASE AGREEMENT
entered  into on August 2,  1996,  but made  effective  January  1, 1996 for the
property  situated in Harris  County,  Texas,  commonly  known as 6401 Southwest
Freeway, Houston, Texas.

Both parties  hereto  hereby agree to extend the term of the SUBLEASE  AGREEMENT
for one year, with the sublease hereby extended  through  December 31, 1999. All
other terms,  conditions,  and rental  payments of the SUBLEASE  AGREEMENT shall
remain the same as those set forth in the SUBLEASE AGREEMENT.


Allstar Systems, Inc.                       Allstar Equities, Inc.



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Donald L. Chadwick                          James H. Long
Chief Financial Officer                     President
December 31, 1998                           December 31, 1998