Braindead
What have they been smoking?
I'm setting up my father-in-laws computer over the holidays. You know, slapping on a linux instead of the Win XP that came with it and that stopped working. That kind of stuff.
Since I'm using the opportunity to experiment with Gentoo for the first time I'm compiling lots of kernels and generally rebooting a lot. So I innocently thought I'd deactivate the BIOS passwort he had set.
Bad idea. The Bios (some MSI) had no such option, so I tried entering an empty password. Yup, it accepted it. Entered it again for confirmation and up came the message 'password deactivated'. Cool. Reboot. 'Enter Password:' WTF?!? I hit the enter key without typing anyhting else. No luck. I entered the old password: 'Wrong password!'
Aaargh! The BIOS accepts empty passwords at the setup prompt but not at the authentication prompt!
Braindead. I wish I could just get him a Mac.

Re: Braindead
You might revert to opening up the computer case and adjusting the mother board jumper settings ... or have you already tried that. A good friend of mine did this for me in High School many years ago. Now 8 years later we work together.
I asked him and he said "You usually have to short the "cmos clear" jumper for like 2 minutes.
Good luck