Get a new Windows product key

If your Windows product key isn't valid, if you don't have a Windows product key, or if you lost the product key that came with Windows, you'll need to buy a new one to activate Windows. You must activate Windows online or by phone within 30 days of installation to use every feature of Windows.

To buy a new genuine Windows product key, go to the genuine Windows website, check to see if Windows on your computer is genuine, and then follow the instructions to buy a new product key.

If you already have genuine Windows and want to get additional product keys so you can install Windows on other computers, go to the Additional Licenses website.