I just installed Windows 8.1 Pro as an upgrade from an ISO torrent. I was able to activate my original Windows 8 key successfully. However, I tried to activate my Media Center Pack key that I purchased for Windows 8 and it errors out the first try. When I try to activate it again, it then says "This key won't work. Check it and try again, or try a different key.". Do I have to purchase the key again?