Today, I have read around the internet about eleventy billion questions/answers about installing the Windows 8 Upgrade via various scenarios, the one that seems to be baffling people is this one: Can you install the Upgrade on a fresh, completely empty hard drive, one with no OS already on it and no other drives with an OS hooked up? This is *not* asking if you can do a "clean" install on a machine with an existing OS on it. This is asking basically, if I build a new box with new drive and no other OS on it, installing a larger replacement drive and/or SSD drive, etc. I asked this question over at Neowin forums and wow, the answers are literally all over the universe. From what I can gather, initially the answer is NO, you can't. Users have installed it but it won't activate, the error message is about installing the OS with no previous OS being seen. However, someone posted a registry key that needs to be changed before activation, very similar to the Windows 7 double-install method. The registry key is: Code: [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\OOBE] "MediaBootInstall"=dword:00000000 According to the user who posted that, using the upgrade download (maybe even the upgrade boxed copy) with the upgrade key results in the above key being 1 not 0. It will not activate as such. Changing the key to 0 will allow for successful activation. Seems the TechNET/MSDN version when installed sets this key to 0 out of the box. Some have also said the TechNET/MSDN .ISO will activate fine with the upgrade keys. I have not personally tried this [yet] and can't vouch for the accuracy of this. Would love to know if anyone here tries this and it works/fixes their problem(s). EDIT: MODS, if this violates any rules, please do what you need to do.