If you put a password on your BIOS setup and forget it there are couple of things you can try:

  • Grab your motherboard manual and find how to reset your CMOS. Usually it involves changing a DIP switch and powering on your computer briefly. Beware that this procedure not only resets your password, but all of your BIOS settings.
  • Apparently1 the same effect can be achieved by taking out your clock battery. I've never tried it - so I don't know whether this works.

  • 1 This was indeed true. Thanks.