I used the wrong xp upgrade disk for my PC - I used the xp OS disk I have for my Laptop. I tried to switch disks in the middle of the process. but after crashing the computer and making it unable to boot I was forced to do a repair with the wrong disk and complete the upgrade with it. NOW, I need to change the xp OS Key so I don't have an invalid install and can activate it. I tried MS Key-Update-Tool, but the program won't accept the key. PLEASE HELP.

Welcome to techhelpforum.

What was the O/S before the upgrade?

Is XP running?

Is the "upgrade" listed in Control Panel, Add/Remove Programs?

Have you tried using the "correct upgrade disk" on the current install?