So I've been using Windows 8.1 Pro for a while, activated through KMS Server. However, I had Windows 8 preinstalled on my machine, and everytime I had to reinstall it, I didn't had to put any key, it just worked. I don't use any of the Pro features of Windows, so I was thinking to install my original Windows 8 again. The matter is - the first time I've tried doing so, Windows 8.1 refused my key. It didn't let me go past welcome screen. I think that there was a mismatch between the DVD I was using and the key I had. The matter is: I can't find a proper ISO anywhere! My computer came with a CoreSingleLanguage Windows 8. Is this the same as Core? Is this the same as Single Language? There is a Windows 8.1 equivalent for it? If yes, where I can find it? Thanks in advance!