Any hard drive experts out there?? Hard drive boots up into windows fine from cold, but after about an hour of use it powers down, then spins up again after a short period (a few seconds). It carries on doing this at more regular intervals but takes longer each time to recover (up to 5 mins). Eventually I get a blue screen with Disk Write Error. When I then restart the PC I get an error after "Verifying DMI Pool data" as it is unable to find the Hard drive. Leave it for 20 minutes and it comes back on ok, but after 10 mins or so it happens all over again. Leave it for a few hours and it will be fine for an hour again. Have checked IDE connections, tried connecting the drive to IDE2 instead of IDE1, power management is disabled in the BIOS and in Control Panel, reloaded BIOS defaults, re-installed the original Windows IDE drivers and Bus Master drivers. I get the same symptoms while running Fujitsu Hard Disk diagnostics from DOS. I also have ACTIVE SMART installed but this is not picking up any problems (e.g. Disk temperature is ok) mainly because it only tests the disk every 1 minute and if the disk is working in an "up" state then it checks out fine. Basically I'm all ready to go out and buy a new hard disk - but is there anything else that could be causing this problem? Many thanks.

Back up the important stuff right away. If it were me I'd suspect the hard drive or the power coming to it. Do other devices on the power connector work okay? The clue "powers down" and "power management disabled" lead to a bad hard drive. You could pull the sides of the computer off and see if the hard drive runs longer before quitting (heat sensitive). Some hard drives have a three year warranty and even if you think it might be out of warranty a call to the manufacturer sometimes yields "bonus" time. They may advance ship. Write back here and let us know what you find out.

Thanks for the help Tim. I don't seem to have problems with any of the other devices on the power connector. Active SMART is also monitoring the temperature of the hard drive and it's not showing any problems. I'll certainly put in a call to the manufacturer before going out and buying a new one - thanks for that tip.