There are a number of product key recovery utilities for Windows – Magical Jellybean Keyfinder is the first one that comes to mind, possibly because of the name – but ProduKey is the first I’ve seen that will recover keys from other installations, for example via a local area network or from slave hard drives. It also recovers keys for Office and SQL Server, and at a diminutive 31KB, deserves a place on any technician’s USB drive. It is one of a number of freeware utilities available from the NirSoft website.
Edit: Actually the new version of Magical Jelly Bean has similar functionality, although it’s still in beta at the moment.
