I'm running a homebuilt PC, with these components:
Asus P5AD2-E Deluxe Mobo
Pentium 4 550 3.4 Ghz (HT)
2 GB off-brand RAM
Western Digital 200 GB HD
Sapphire ATI Radeon X800 Pro
Creative Sound Blaster Audigy 2 ZS
Lite-on DVD-RW drive
Samsung CD-RW/DVD drive
About 4 months after I got the system up and running, I had a few hard crashes. When I say hard crash, I mean that the screen immediately went black and the computer shut down, with no warning whatsoever. I assumed that this was overheating, as I believe that's usually the cause of that kind of activity, and the cooling was never great in my computer. I replaced the (then stock) heatsink with a very nice one from Arctic Cooling, and saw the running temp drop about 8-9 degrees C. However, the hard crashes continued, though sporadically. I would have weeks at a time where there would be no crashes, and then two in one day, seemingly randomly. I am now pretty certain that it is not overheating that causes these crashes. It has crashed as I've watched the temperature monitor, which usually hovers between 30 and 35 Celsius, FAR too low to overheat. I thought it may be the video card overheating, but this doesn't make sense because I could play games for hours without incident, and it crashes even with the case open and a fan blowing into the case. Also, these crashes seem to happen particularly often while burning DVDs, no matter what software is used.
Then, a few days ago, I had a hard crash while watching a DVD on my Samsung drive. When I restarted, I was able to take the DVD out of the drive, but then it hard crashed a few seconds later; before it had finished booting up. When I started it up again, the drive was no longer recognized by the BIOS, even after un/re-plugging it in and flashing the BIOS. Also, since that incident, I have had several hard crashes per day.
Needless to say, I'm extremely concerned about this, and don't know what to do. I know it's less than healthy for the equipment when it hard crashes, and I'm sick of it too. I don't know why my computer is doing this, and I have no practical way of testing each component. Does anyone know what could cause this behavior?