I almost through my computer out the window once. Course that was a long time ago.
Anyway, it depends what you mean by "locked". If the problem is a password (go into BIOS and it asks you for a password to proceed) then flush the BIOS settings by opening your case, locating the BIOS Jumper (look on the manual to find where this is to), unplug the computer, short pins 2-3 for a few seconds, then change the jumper back to its original setting (pins 1-2), plug the computer back in, and the BIOS should load default settings allowing you access. Alternately, remove the battery (you'll see it, it looks like a watch battery). EDIT: You must replace the battery a few seconds later.
If this fails, there are a number of good utilities to change all manner of BIOS settings through windows.
Daniel