Updated my BIOS and found myself unable to boot into windows. Ended up finding out it was because of a setting called "Wait for F1 if Error" in Advanced Boot settings. Apparently ASUS motherboards get confused if you use liquid cooling, because I always got a CPU Fan error at startup. So I disabled CPU fan speed, and then I could boot into Windows. A weird thing was that I could boot into windows if I pressed Escape on that Advanced Boot options screen, even if the "Wait for F1" setting was still enabled. Why was this?