At this point, I would just say it's some sort of software error, throw in a different hard drive and attempt to install your OS on it to see if it works.
Yeah I was thinking software error too. The thing is this crappy dell only has 1 SATA slot/port whatever and I don't even have any spare drives. I'll order one soon. Might as well order a whole new set of parts and get a decent system and make a media center out of this one.