Toshiba
I know that for a Toshiba you have to send the newer machines back to the factory and they clear the password there and it costs $50 or $100 or so. Although if you can get the machine booted into a command prompt you can use the debug commands in aprevious post and it usually will work. I think the debug script is the best thing to use. Although the memory ranges he specifies is rather short. I don't remember exactly, but I previously would use something like this.
debug
-o 70 00
-o 71 ee
-q
That will make sure that you clear everything in your bios settings. Basically what happens is you force a rewrite of the stored bios information from the Flash ROM.
