Activate an Invalid Copy of Windows Without Reinstalling
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!