Important: I highly recommend that you back up the registry keys you're changing in these steps as an extra precaution.
If you're uncomfortable making registry changes in order to change your Windows XP product key, using the popular free product key finder program called Winkeyfinder is another option.
Microsoft’s Windows 10 was commercially released in June 2015 and it received mix reviews.
Changing the product key that you used to install Windows with might be necessary if you find out that your current product key is...
well, illegal, and you've purchased a new copy of Windows to solve the problem.
While I think it's less common these days, many people still use product key generators or other illegal tools to get product keys that work to install Windows only to find out later, when they try to activate Windows, that their original plan isn't going to work out. You can change the product key manually by making certain registry changes or by using a wizard available in Control Panel. Since some versions of Windows use slightly different names for some menus and windows, pay close attention to the differences that are called out in those steps.
Note: The steps involved in changing your product key differ considerably depending on which Windows operating system you're using. It's important to take great care in making only the changes described below!
The same is true for Service Pack 3 (SP3), which appeared on 2008-05-06.