Find your Windows product key - support.microsoft.com
support.microsoft.com › en-us › windowsLocate your product key for Windows 7 or Windows 8.1. A product key is usually required when uninstalling or reinstalling Windows 7 or Windows 8.1. Generally, if you bought a physical copy of Windows, the product key should be on a label or card inside the box that Windows came in. If Windows came preinstalled on your PC, the product key should appear on a sticker on your device.