UPDATE: welcome First.org readers!
Here is a handy tool. I really like the fact that this tool can run from a USB key (yes, this can be used for good or evil)
The Magical Jelly Bean Keyfinder is a freeware utility that retrieves your Product Key (cd key) used to install windows from your registry. It has the options to copy the key to clipboard, save it to a text file, or print it for safekeeping. It works on Windows 95, 98, ME, 2000, XP, Server 2003, Windows Vista, Office XP, Office 2003, and Office 2007.
I tested this on an XP machine for which I already knew the keys. It worked just as advertised. A very simple, handy little utility.
[tags]Keyfinder, Tools, How To[/tags]