Helo yohan. So bad I couldn't help. Since you had like to really try win8.1. I wil advice that you do complete back up of your system. Then get pen drive or dvd for win8.1 and do a clean installation.
Instruction is here; http://is.gd/A1oH6y
I hope that helps
Instruction is here; http://is.gd/A1oH6y
I hope that helps