Warning! Do NOT apply XP SP 3!

[se5a]

Xrati said:
David, for a complete bios reset, just go to the motherboard and take the battery out for ~1 to 2 hrs., OR leave it out overnight. When you reboot, all the bios setting will be at default and you should be able to access it through your 'F8' key or 'delete' key on bootup.

There should be a jumper which will do the same thing in a matter of seconds, look in the mobo book, or if you've not got that, find it online.
it may even be writen on the mobo, something along the lines of clrcmos or ccmos.