In Win9x/Me, the PK is indeed in the registry, easy to find, and plain as day. In all versions of Windows from 2000 up, the PK is in the registry, encrypted as 'Digital Product ID'. It's also in the file C:\windows\system32\config\software as an encrypted number (WinXP, maybe W2k also). That's why we use 3rd party apps to get key. As far as Vista is concerned, I don't know 'cuz I haven't messed with it that much.