LIFE-TIME GUARANTEE.
In order to upgrade your system to Windows 8 or Windows 8.1 please go here:
http://windows.microsoft.com/en-US/windows-8/upgrade-product…
In order to do a clear installation of the system please use this link:
http://go.microsoft.com/fwlink/p/?LinkId=271128
Full video guide: http://answers.microsoft.com/en-us/windows/wiki/windows8_1-w…
Legitimacy: https://www.trustpilot.com/review/www.gamers-outlet.net
Msdn licenses? If not would be a good time to buy for the upgrade to Windows 10 pro as you can turn off auto updates