I upgraded from windows 7 home premium to windows 8 pro with my valid product key that i purchased from Buy Windows - Microsoft Windows for $39.99 with ease. Then I requested a free media center key from windows here Add features - Microsoft Windows and i have still have not received the email. (I know i was stupid but,) I told my friend and he put his key in the the add features box and it says its valid and works for three hours. Then a blue screen pulls up asking to activate windows so i put in my valid product key and it says "This key didn't work. Please check it and try again, or try a different key". Under "Current product key" the last five digits do not match my valid product key. I'm assuming that the add features changed my product key and also my windows version so it wont activate. Kind of like using a Windows 7 home premium key on a Windows 7 ultimate os. I was looking around in the windows 8 help and found this Add features to Windows 8: Frequently asked questions that you cant remove added windows features unless you do a clean install. Which i don't believe i can do because i have a upgrade key.
I assume your friend had already used the WMC key and that is why yours stopped working. You may have to re-install Window 7 and then your Windows 8 Upgrade key will work. I know it is a PIA. I make a image on my system before I do any updates so if something goes wrong I can restore back to the original. Also look at System Reset as it lets you restore to a clean version of Windows 8 and asks for your key. I do not know if it will work with the Upgrade key or not but may be worth checking.
