For me the problem came from Windows updating itself to the Newest build named "Pro Insider" I've already stopped it from doing this twice but did it overnight while I was asleep.
Because that new build was buggy as all crap to the point where I couldn't even get past the login screen I rolled back to 9926 (what I wanted anyway) Since then I cant open the Start Menu or the notification center, co-incidentally, these are the two things I opened in the new build before deciding to restart my computer after updating my GPU settings.
I've tried the powershell option all I get is access denied. Ive tried the regedit option and restart and nothing.
i5 4960k, 8gb 1866 ram, 120GB SSD, 64 bit Windows 10 9926 (roll back)
For the record in case I end up doing a clean install, is there a way to totally disable Windows from updating to the latest builds, there doesn't seem as much options in the update centre and this build worked flawlessly before the update screwed it up lol