so I upgraded my computer from windows 7 to the windows 10 insider edition a few months ago. I just finished upgrading my computer today from the insider edition to the official windows 10. under updates it says I will still get insider builds though. anyways I can not seem to activate my windows 10 now though. I tried using my old product key from windows 7 (I keep all that kind of stuff) but I just get an error. so now I have a un-registered version of windows 10 and I don't know how to activate it.