You don't need to borrow a key!!!!

As long as the registry is still readable there are ways around it.

I had to do this a few weeks ago, take a look at this website:

http://www.dagondesign.com/articles/...-key-recovery/

Worked a treat for me.

You will however need some form of access to the contents of the hard disk, so take it out and borrow another PC for half an hour or something. Format it and you've lost it forever.