My PC run into a problem after diagnostic startup

I've done a few tinkering with my laptop a while ago then out of curiosity and attempt to speed up my laptop I clicked diagnostic startup on msconfig. Now, upon restart, my lock screen shows this message " Something happened and your PIN isn't available". I click set up my Pin and it doesn't work! I've tried a system restore a while ago and it doesn't work too. Safe mode (the thing where you press F4/F5) from system recovery doesn't work as well.