Alright, so check this out:
6/4/09: Computer was running smoothly.
6/5/09: I turn the computer on and instead of booting Windows Vista, it boots Acer Arcade Deluxe. I click to exit from it and it restarts the computer entirely. Then, to make things worse, it flashes a load bar at the bottom of a black screen that is titled: Windows is loading files. Then it has the Microsoft load screen. Then it goes to a grey screen, saying that it failed to start up and startup repair could not automatically repair the error.
Anyone have any idea what might have happened?