I recently had a massive crash on my Windows 8.1 partition, which has rendered it (practically) unusable. I tried to do a refresh, but the problem is, I have a Windows 8 install disk, not 8.1, and thus it didn't work. I also do not have any system restore points/backups of any sort, but I have managed to move my files off. Also, I do not know where my product key is (and cannot find it online), so a clean reinstall would not work.

My question is, is there any way to change my Windows 8 disc into an 8.1 disc to allow me to refresh/reset my PC, or is there any other way to do this (aside from repurchasing?)

Thanks!