What is the chipset number on-board? Intel PRO100+ with intel GD82559 + Atmel AT49BV512 perhaps?
If yes, then check this Intel web page for driver availability:
And also check the driver link in this thread:
And then there's always the HP/Compaq website to check for driver availability:
And last, please use our Driver Search Wizard
to see if it's posted in our driver database.