Its still a power manglement issue (misspelling intentional as this is a common term among us computer guys, say for example "middle manglement mangled that project again"). There were some hard drives a while back that had a firmware that would power them down and ignore what the computer told it to do. The maker gave in a released a flash upgrade that fixed the issue. I have an old pc sitting upstairs that locks up the same way. I ended up disableing the power manglement in the BIOS setup and just leaving it run all the time.
Interesting note somewhat on the subject. There was an ad before the start of the movie I watched tonight asking how much power would be saved if everyone in America unplugged all their TV's. For those that don't know the picture tube in a TV has a small heater in it (any other vacuum tube does as also) Years ago you had to replace TV's every few years until the tube designers found that keeping the heater powered up at all times extended the life of the tube many times. After a couple other ads they came back with the answer of something huge like 8 billion watts but what they fail to realize is how much power would be wasted replacing tv sets every 3-4 years instead of every 10-15 years(my magnavox from back when they were still US made still looks great for example). I've learned that shutting off pc's causes more problems that leaving them run all the time so I've switched to running laptops and other lower power pc's so I can justify leaving them on all the time. If you buy a PC with a slower processor you can save a bit of power and also save enough money to buy more ram (and windows handles ram very poorly so the more the better) and have a faster pc than someone with bragging rights to a faster cpu.
Anyway, my point was that you don't need to be scared, your hard drive isn't failing you just have a pc with bad power manglement. The old box I have upstairs has ran for 4-5 years that way (Pentium 166) and has the original hard drive.
