Upgraded to Windows 10: Your computer does not have a product key, in case you upgraded to Windows 10 operating system from a previous version of Windows (Windows 7 or Windows 8.1). In all such cases your PC has been registered on Microsoft activation servers with a digital entitlement for Windows 10 that will always be used to activate Windows 10 on your PC. Windows 10 bought from a retailer: You will find the Windows 10 Product Key on a label inside the Windows 10 box, in case you bought your copy of the operating system from an authorized retailer. New Computers: New computers that come pre-installed with Windows 10 operating system will have the product key installed or embedded in the computers UEFI (Unified Extensible Firmware Interface). On new computers, you may also find the Product Key displayed on a sticker inside the box. Do You Really Need to Know Windows 10 Product Key It is safe to assume that you will never come across the need to use your Windows 10 Product Key during regular or everyday use. Microsoft appears to be doing away with product keys, and it is perfectly possible to reset or reinstall Windows 10 operating system on the same PC without having to enter the Product Key. Whenever you reset or install Windows 10, the product key will be automatically detected from the UEFI chip of your computer and Windows 10 will be activated on your computer.