Well the only thing that I can think of is "Usually a company will have their employees sign an understanding of these issues but who knows.(like stated before)" and if so then the only question I have is. Is this a network password? if so then can't it be resetted? that would be the simplest way, that you could tell them to do it themselves and a way to keep you out of the legal process

Personally I would of unlocked it myself after they show me proof that the PC is indeed theirs. Then copy the needed files off and leave the files on the PC as is.

Once again, I am kinda blind to legal stuff I have a habit of looking at stuff logically. thats my option