Originally posted by: chsh1ca
I'm pretty sure XP stores it the same place in the registry that Win9x and Win2K did. If so, it should be in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\ProductId
EDIT: Yep, just verified this on my brother's XP Pro machine.
Originally posted by: monzie
I find this little app useful:
http://www.magicaljellybean.com/keyfinder.shtml