Ok, so I got the parts for this build around December '08 and January '09, and it worked great up until a couple of weeks ago.
The computer will run fine for a 3-4 days, and then it will crash during boot with DISK BOOT FAILURE, INSERT SYSTEM DISK AND PRESS ENTER. Sometimes, if I reboot, my OS will boot, but then later it will crash for good.
So every time this happens, I have to wipe the hard drive and reinstall the OS. I've reinstalled XP Pro several times, tried XP Home Edition once, tried Ubuntu 8.04 Hardy Heron twice, and Ubuntu 8.10 Intrepid Ibex once, and all end up crashing with this error.
Furthermore, I've tried installing XP Pro on two other hard drives, and both times they have crashed with this error, so I think something must be going on with my hardware.
I also successfully flashed my BIOS to the latest version, but that didn't fix the problem either.
Any help is greatly appreciated. I really don't want this computer to be done for good.
Check all your cables and connections for integrity and tightness. Also, switch your power cable to one on another lead. Your motherboard is losing communication with your hard drive for some reason. If your hard drive is NOT going bad, then either the data cable/conection is faulty or you are losing power-again due to a faulty cable or connection. It's obviously cheaper trying different cables and connections first. (I personally don't like anything on a power lead with my hard drives. I've had conflicts before, too.) Good luck.