I had upgraded my windows 7 home premium 2 days ago to windows 8 pro (my friend gave the upgrade to me through his USB-stick with a working activation code). Yesterday I booted up my PC and saw "preparing automatic repair" then "diagnosing your pc". I tried to start up on safe mode and it didn't matter what kind of startup I chose. It would always show the "preparing automatic repair" and so on. It's an endless circle. I don't have any image back-ups. I have somme back-ups but they don't work with Windows 8. C

Extra: I want to restore it so I can downgrade it again to a Windows 7 pro. Because Windows 8 is ununderstandable and is useless to study IT. It's not recommended to use it.

Assuming you simply did an in place upgrade you may have the option to run a system restore to recovery your Win7 OS.

It is also possible that it recognizes that your computer is not the computer the upgrade was meant for. So it is trying to figure out what to do. Often times that code is tied to a specific class of computer unless you purchase the generic copy from a store.