This will be long, but it was certainly strange... A couple weeks ago, a lady asked me to look at a computer I built for her about 4yrs ago. Computer was giving a "disk failure" error upon boot. I of course immediately suspect hard drive failure. I boot it at my house, and use the computer for an entire day without issue. I told her it was working fine for me... so she comes picks it up. 3 Days later, same problem.. she brings it back. I boot it at my house, no problem. I went ahead and swapped the SATA cables just cuz I figured that could be a likely issue, and used it again for almost an entire day... No problem. Yesterday, she brings the PC back.. I still have no problem. So she comes and picks it up, and has the problem within 20min of getting home. So this afternoon I drive out there to see if it's something local. I turn the PC on, and sure enough, boot disk failure. I open the PC up, pretty much unplug everything except the hard drive and the keyboard. Machine boots up perfectly. Shut down.. Plug in the mouse, boots fine. Proceeded w/ shutting down and plugging in all the external devices one at a time, and all was fine. Plug the DVD drive back in.. bam... Disk boot failure. So I disconnect it, check the BIOS to make sure the hard drive is first in the boot sequence (it is).... Machine boots no problem. I shut down, plug DVD drive back in, Disk boot failure. So I unplug the hard drive from the motherboard, and plug it into the SATA port the DVD drive was occupying. Boots no problem. Plug the DVD drive back in to the SATA port the hard drive was initially using, boot disk failure. Anyone ever had a bad DVD drive cause a machine to not boot? I've got a new DVD drive here, I'm gonna run over and put it in tomorrow and see what happens. For now, I've just left her DVD drive disconnected, and it seems to be fine.