After finding this on Google:-
I thought I'd have a look through Conpaq's website and brave it through the support section(!) I've stumbled across this:-
Not hugely detailed I grant you! But the solution may work. If you have a manual for your Compaq still, then have a look through to see where to reset the BIOS. There is usually a little jumper (a bridge that connects two pins) that you have to move on the main motherboard on your computer.
Good luck and let us know how it goes