There was a game which was not working properly. I've found a fix online, but I've deleted the wrong dir. (yes, that was just dumb)
I had to delete this:
HKEY_LOCAL_MACHINE > Software > Microsoft > Windows > CurrentVersion > Uninstall > Origin (DELETE FOLDER)
And I deleted CurrentVersion. Now my PC won't boot up (it tries to repair itself but it can't - according to the logs it creates the error can't be found)
What are some options to deal with this?