Have you tried a different power connector.. on a different power segment if nothing else is on that one. I've seen both bad power connectors in a segment from PSU's and also whole segments not work.
Yeah, I did. Two different power connectors, each on a different segment. And I also know its not a problem with the data cable, because like I said, I took it out of the optical drive and plugged it into my hard drive, and the bios still recognized it just fine. But when I went to plug it back into the optical drive, nothing.