So I recently cleaned my pc. I plugged everything back in and it booted up fine. The next day I tried booting and and it booted to a black screen with a non-blinking white underscore that's about halfway between the center of the screen and the top left corner. If I leave the pc on when it boots to this eventually it will boot normally. I have reset the cmos but I haven't done anything else. Any idea what it could be? Once I'm in windows everything works fine.