AS I read in several thread's an many post's, everybody is able to do just a clean install of Windows 8 Pro using an bought legit Key! I was try that on an new 750GB Hdd using an USB Stick with the images downloaded using the WUA. The install starts and I could pass the first screen.Second screen the button for install isn't usable and I could use the Repair button only. Result: I'm not able to directly do a clean install of Windows 8 Pro! Now I'm in process to first install Windows 7 Ultimate and wen that is done I'll try to do a clean install again, without to activate first! Will report back if I succeed or not.