|I'm afraid there's not much to do. If it's the very first thing that comes up (before Windows loads) then this is a BIOS password and there aren't many ways to reset the BIOS password, short of wiping the BIOS and starting again (as far as I'm aware).|
Not for the feint-hearted.
If it's your computer, how did the password get set if you don't know it? Find the person who set the password and ask them.