What happens when you discover your copy of Windows is invalid? You probably will get a Windows Genuine Advantage (WGA) notification informing you that you’re illegal, and you need to purchase a legal license.

This can happen for a number of reasons, and not simply piracy. Perhaps you bought a computer second-hand and were told your Windows install was valid, only to find out later that it wasn’t. That’s a pretty common scenario, and a darn annoying one. If you search the net and Microsoft’s web site for a way to activate your copy with a legal key you purchased, you may find yourself in a bit of a mess.

You see, it isn’t terribly obvious that you CAN in fact simply activate Windows XP, Vista, and Windows 7 with a new legal key – and without reinstalling anything at all. Finding the information on how to do this is rather difficult, and I’m not sure why.

Not to worry though – it’s a piece of cake!

First of all, let me just add here that this post will not tell you how to illegally use any Microsoft product. If you’re looking for a keygen or an activation hack or something, you’re in the wrong place.

Alrighty, now that that’s out of the way…

I recently ran into this problem, and I was pretty peeved when my Google searches turned up only info on how you must reinstall if you have, say, Windows XP Corporate Illegal, and you want to purchase and use an XP Pro Retail key with it. Even Microsoft’s own tech support peeps were not much help. Reinstalling seemed to be the only option, which was seriously frustrating.

Then I stumbled upon a real solution, which involves actually downloading a little app from Microsoft itself to change your product key without reinstalling. Go figure! I guess the tech support people were out of the loop on this one…

First, I should mention that if you’re using Vista or Windows 7, the process is even simpler:

1. Click Start
2. Right click “Computer” and choose Properties
3. Scroll down and click “Change Product Key”
4. Enter new product key and validate

Wasn’t that easy?

If you’re trying to legalify a copy of Windows XP, the process is only slightly more complicated:

1. Download Microsoft’s Key Update Tool for XP
   (if link is dead, try downloading here instead)
2. Run it, and enter your new key
3. Reboot, and you’re done

Wasn’t that easy?

Of course, you WILL need to have or purchase a legal Product ID Key to use with your copy of Windows, and you can only use 1 key for 1 computer. But at least now you don’t have to listen to the bozos on the net who claim that you must always reinstall Windows in order to make your copy legal!