So I forgot to deactivate my machines before formatting them a few months ago, and they have the $15 Windows 8 Upgrade keys. So wondering a few things: Can I simply download an 8.1 Pro ISO, and punch in one of those keys, or did MS shut them down? Can I use said keys on another machine (they seemed retail to me, but not sure) by using 8.1 Pro ISO and punching in said key? Also one more bonus question! I have 1 machine that went KMS 8.0>8.0 Windows 8 with Media Center (loophole, was an obsolete machine but I want to give it to a family member and put a real licence on it, such as one of my $15 upgrade keys). I never upgraded that 8.0 with Media Center to 8.1, as I was worried it would revert to Non-Genuine. I HAVE NOT formatted that machine yet. Is there anything I should backup if say, I wanted to reuse that licience (if its reusable)? Thanks.