|The best would be from Compaq support.|
However if not available for your new o/s, try to identify the chipset used, which should be detailed in the mobo manual, and google for a generic driver for such.
However, you may encounter a problem as drivers sometimes are modified by the pc makers.
It might be easier just to add a sound card, which would probably perform much better than the onboard sound anyway.
Advise back how you get on.
Good Luck - Keep us posted.