If you upgraded from Windows 7/8.1 to Windows 10 or plan to do so in near future, you probably are aware that you need to upgrade your current Windows 7 or Windows 8.1 installation to Windows 10 in order to get the free upgrade and it’s not currently possible to activate Windows 10 using your Windows 7 or Windows 8.1 product key.
Microsoft’s decision not to let users activate Windows 10 using genuine Windows 7/8.1 key has forced many users upgrade their Windows 7/8.1installation to Windows 10 even if they wanted to perform a clean install of Windows 10 from ISO. Although once the Windows 7/8.1 installation is successfully upgraded to Windows 10 and activated, it’s possible to easily reinstall Windows 10, many users are experiencing activation issues after the clean install.
Actually when Microsoft released Windows 10 final RTM version to public, they announced the free Windows 10 upgrade offer which allows existing Windows 7 and Windows 8/8.1 users to upgrade their computers to Windows 10 absolutely free within one year of Windows 10 launch. But to take the benefit of this offer, users need a genuine and already activated Windows 7 or 8/8.1 OS installed in their computers and only after that they can upgrade the existing Windows version to Windows 10.