There should be a BIOS re-set jumper on the board - will be somewhere close to the battery - try this first. If this doesn't work, try removing the battery for a while (I would suggest at laest an hour), then reinserting. One of these should do the trick.
use a flathead, and reset the cmos, then load bios defaults. theres 2 solder points by the baterry it should say cmos by it
short em out and it should reset it. touch em both with the flathead for atlest 30 sec.