My PC has WinXP Prof upgrade installed, based on a full Win98 disk. Let's say I now install Win7 Prof upgrade. What would happen if I install XP Prof on another computer? Or is the XP license now defunct and will be rejected when I try to validate it on the other computer?

Hi Leo854: The Win7 Upgrade will assume the license of your previous XP Prof installation and should you re-install XP Prof again validation will show that "your license is already in use"......meaning it's now being used by the Windows 7 installation. To continue to use your XP Professional license you would have to buy either an additional full retail version of Windows7 or an OEM version.

Is this for retail versions of XP or only OEM versions?

Is this for retail versions of XP or only OEM versions? Either version. You can no longer use the qualifying Windows XP license by itself again unless you uninstall Windows 7 Upgrade by reformatting the hard drive.Carey Frisch

OK, Carey, thanks. Now I am wondering...what happens if I have problems and have to revert to Windows XP on the same machine?Example: I ran the Windows 7 Upgrade Advisor and it fingered several drivers and said they would need updates from Windows Update once Win7 was installed. If there are none, I will have to go back to Windows XP until there are...