Hard drive caught on fire this weekend...
I had this problem that would randomly appear with my Maxtor 120 gig HD. I would be playing a game and I would get a "BEEP" from my speaker and then the CPU would lose contact with the HD. If the thing didn't lock up completely I could exit the game and go out and try to see the hard drive and it had disappeared completely. Sometimes I could reboot and it would show back up again. It did this every once in a while. I thought it could be a voltage problem so I redid some of the wires but it still didn't fix it.
This weekend it did it again so I took the cover off the computer, made sure everything was OK, pushed the plugs in, etc, etc. Even after rebooting it five or six times it would never see the drive. So finally I unplugged the power cable and the ATA cable and plugged them both back in just to make sure I had good connections. On the next reboot I got a nice spark from the underside of the drive and some 2" flames for a few seconds. I went into panic and shut down the power. The HD has a nice burnt hole in one of the chips now.
Luckily this was my secondary HD with most of my games and shit on it. i just replaced with a new 160 gig. Never heard of one catching on fire though! Funny shit.