Magical Jelly Bean Keyfinder is a small tool that can reveal your registration code from the registry, that you used to register your copy of Windows. It will also display your product keys for Microsoft Office. It works on Windows 95, 98, ME, NT4, 2000, XP, Server 2003, Windows Vista, Office 97, Office XP, and Office 2003.
Download: Magical Jelly Bean Keyfinder [1]