Great, I just had to reinstall Windows 10, because of a broken BitDefender!!!
After I rebooted my PC and logged in, Windows Explorer would suddenly start to flicker. I disabled all Autostart items, with no success. I rebooted into Safe Mode to uninstall BitDefender to see wheather it was causing the issue or not, but I could not uninstall it. After hours of wasting time, I decided to reinstall Windows completely.
Well, right after a fresh install, the first thing I installed was BitDefender Total Security, and rebooted. Guess what, the flickering started again. This time, I was able to uninstall it in Safe Mode. Rebooted -> Flickering didn't occur anymore.
Never ever - BitDefender! (Cool, it even rhymes)