I seem to have a hard disk problem that prevents my computer from booting, but it randomly lets my computer boot if I shut it down and wait for awhile. I have a Dell optiplex GX260 that I bought off of e-bay. It's a pentium 4 and when I first bought it it was working fine. I usually leave my computers on for many weeks at a time, but one day when I went to the computer it was unresponsive and the screen remained black. I restarted the computer and I came up with this error, however when I shut the computer down and waited a few hours then rebooted it, the error didn't come up and it worked normally. My OS is windows XP pro.

This exact same condition happened to an older computer of mine, a pentium III running windows 2k. However the computer randomly shut down and gave me the Hard disk could not be found error. I'm worried since two different computers are coming up with the exact same problems. I don't think it's a hard driver error, but when I go to BIOS and try to auto detect the HDD it cannot located it on either computer. Then a few mins of shut down time magically fixes the problem. Can anyone help me out?

My first thought is shutdown time = cooldown time. How are your temperatures?

The computers you mentioned are quite old. Replaced the CMOS (BIOS) chip battery. Usually a type 2032, 3V, lithium battery, which you can find easily in stores. If that doesn't fix it, it may be some other problems.

Hmm the CMOS (BIOS) chip battery might be the issue, but I have no clue where it is or what it might look like. I don't want to accidentally mess up my hardware.