Here is the easiest way and it is certain to work: Go through the following steps: *Buy the license first. *Download Key Update Tool, a utility provided by Microsoft to change the key of the Windows version installed. Link Id=50346&clcid=0x409 *Double-click the utility will then check the system files.
These products are no longer actively supported by Microsoft.
No further development will take place on these products and security updates are no longer issued.
Restart your PC once you’ve done, and your copy of Windows should be “genuine” again.
If you’re having trouble then there are a number of third-party tools that will attempt to do this for you.
There are also a few applications that will attempt to remove WGA for you (more on those later).
It is worth mentioning if you’ve re-installed XP lately and downloaded WGA in a recent update then a simple System Restore and delete them, just in case.
Do you have Windows XP without the genuine serial key?
Don't worry -- with a few clicks of the mouse and a little bit of cleverness, you'll be able to make your Windows XP genuine forever.
If you’ve got an old PC that doesn’t need the bells, whistles and expensive licence that comes with Windows 7 then XP is still a viable alternative.