Product keys included in the box the Windows DVD came in. Product keys included in the confirmation email you received after buying Windows from an online retailer. Product keys included in the packaging or the Certificate of Authenticity (COA) attached to your PC that came installed with Windows. The following types of product keys are supported: Windows 8, or Windows 8.1 product key to activate During the free upgrade or installation, you can use a valid Windows 7, Starting with the November update, Windows 10 (Version 1511) can be activated using some Windows 7, Thank you for contacting Microsoft Community. Window 10 installation and activation using Windows 7 Product key
