I bought a notebook that came with windows 7, so I used the $15 offer to upgrade to windows 8. I didn't save the product key I got.
Then I did the free upgrade to Media Center pack, which got me a new product key. This one was also sent to my email.
A month later I bought and installed another windows 8, for my desktop, using the same email address. This time I saved the key in a file. Later I upgraded this machine to Media Center too, because it was still a free upgrade.
When the upgrade was finished, my Windows was no longer activated. This happened because I got the same product key than my other WMC instalation. I got the same one because I used the same email address, even though they were different windows installations. I researched and it seems that the WMC key was also tied to my email address.
The only solution is to reinstall windows 8 pro on top of the WMC install. This is a PITA, but something I can do.
The thing is, now I have two WMC installations with the same product key. I have one W8 pro key from my second buy, because I saved it on a file. I need the W8 pro key from my first buy. I want it because I paid for it, and I have no idea where to get it.
So where can I get it?