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For the last few weeks my PC (pretty old P4 with Windows XP SP3) has been crashing randomly. It just suddenly reboots instantaneously. It feels hardware-related but I wasn't able to determine whether it's software or hardware that causes it. I did notice a pattern though: it's more likely to crash whenever I copy a lot of files over network or have uTorrent running, but sometimes it crashes when I am not doing anything with it.

Copying files from it over the network causes it to crash within 1 to 10 minutes almost every time. Using torrents causes it to crash every 1-3 hours. With neither of those taking place, it crashes every 24 hours or so.

I have ruled out the following probable causes:

  • PSU (I bought a new one and turned off most of the drives so the power is sufficient 100%)
  • Bad HDD or interface cable on my SATA disk from which I was originally copying the data over network (bought new SATA cable and later yanked out the HDD completely, PC still crashes without it)
  • Video adapter (AGP slot is now empty, using the onboard VGA at the moment)
  • Network adapter (removed it from PCI, using onboard LAN)
  • CPU (I think: I changed the thermopaste and its temperature is below 50C)
  • RAM (I think: I ran Memtest86 and it didn't show any errors)

At the moment I only have only one system HDD and DVD drives, a mouse and a keyboard plugged in.

The fact that it crashes more often when I use the network extensively makes me think that perhaps it's software related (I removed the network adapter from PCI and now am using an onboard one, so network hardware is unlikely to cause problems). I am now pondering a system reinstall but it's not a pleasant solution so I decided to ask whether there are any better ideas first. If someone can share a good diagnostic tool it would be great because I didn't find anything good.

Note: the motherboard is actually ~4 years old as I replaced it back in 2007.

share|improve this question
@Tom Wijsman: don't want to sound rude, but have you actually read the question? I mentioned that I unplugged GPU, that CPU temperature is fine (HDD temperature is also fine) and that I checked the memory. Other than that, no overclocking, it's the same setup that worked fine for the last two or three years – Dyppl Jun 26 '11 at 18:38
Your question only listed the CPU temperature. Have you checked the event log and drivers like I mentioned in my previous comment? I've immediately removed it because I thought you were right. – Tom Wijsman Jun 26 '11 at 18:49
@Tom Wijsman: yes, I looked into error log but I am not good at interprerting it. There are some error messages but it's hard to tell wether they were added the moment the crash occured. Can I provide some info from error log to maybe give you an idea? Which part of the message is relevant? – Dyppl Jun 26 '11 at 19:00

Firstly, when you say crash, do you mean a bluescreen and a quick reboot, or a full on hang?

If it is a bluescreen, you can not rule out hardware, but you should be able to use Nirsoft Bluescreen View and get a bit more information.

If it is a pure hang, it is most likely hardware that has gone faulty.... probably the motherboard.

If it is a P4 era machine, have you checked for faulty capacitors on the motherboard?

alt text

The top should be almost flat (with slight indents out embossed sections depending on specification... look at the middle one) but you do not want to see any big bumps such as the first one or any leakage as the last one.

share|improve this answer
no bluescreen, it's just black screen and PC is booting up again. I'll check for faulty capacitors, but I think it's worth mentioning that I replaced the motherboard about 4 years ago (it is still pretty old though). But how would copying files over ethernet trigger such hardware issue? – Dyppl Jun 26 '11 at 15:23
Simple... Many things use the chipset - the more intensive the job you are doing, the more common you will see crashes. – William Hilsum Jun 26 '11 at 15:51
@Dyppl Could you check if your CPU is overheating? Transferring files over Ethernet generates a lot of CPU activity. For an old computer, dust in the fan and heat sink can serious impact cooling. – Aug 2 '11 at 20:43

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