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I have had a lot of viruses on my PC which I have removed. I seem to have developed a problem and maybe an important file has been removed as a false positive. I'm not sure. My PC (Windows XP Home SP3) randomly powers off. the last (and only) error in event viewer is as follows:

Source: Service control manager Type: Error Category: None Description: The Network Security service terminated with the following error: The specified module could not be found.

I can't seem to find anything on this Network Security Service other than it might be something to do with Mozilla Firefox? which I do have as my main browser.

I am posting this now in safe-mode with networking which appears to be the only ay to use this PC at all at the moment.

Any ideas on how I can troubleshoot this please. Thanks.

UPDATE

I managed to back up all my files from My Documents in safe mode onto my second partition. There must be some driver and associated hardware not being used in this mode.

I replace the power supply.

I downloaded the latest BIOS flash image from the internet using someone elses computer from the manufactureres site and flashed the BIOS from a floppy disk, this worked fine with no problems first time.

I then started an XP install and deleted my primary partition, created a new one and formated it with NTFS. I chose a full format not the quick format option. Once the set-up gets to graphics mode but before setting location and network settings the PC still just powers off with no warning.

No matter what I try to install on it (Ubuntu, puppy) it will just power off at some random point during the install process. Almost immediately in fact with any of the linux flavours I have tried.

Booting from a live CD has the same result.

It looks like I have some hardware damage somewhere. Maybe my graphics (on board nvidia chipset) or the memory module, or maybe my NIC (also onboard)

Another suspect: The mobo has a 24 pin ATX power connecter, there is a sticky yello label over the last 4 pins and I have run this machine for over a year with a 20 pin connection. Maybe if I get an adapter or a third power supply with a 24 pin connector and remove the label this might magically stabalise things, but I doubt it at the moment.

Next steps: I intend to burn some diagnostic bootable cd's and test some of the components individually. I'm in no rush now as I have purchased a laptop to get me back up and running as it is becoming increasingly likely my PC is fubar.

I have no idea how the hardware got damaged, we've no power outages or surges that I'm aware of and I am 99% percent certain the array of viruses that had got passed my defences were not capable of damaging hardware.

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2 Answers 2

I think you still have a virus. Since you said you had removed them, they probably fooled your antivirus program. I think that you should reformat you hard-drive. Don't back stuff up now, because you files could be infected.Even then, you still might have a virus, if it hides in your BIOS. Good Luck.

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I think Dynamic may be being a bit paranoid, yes you probably have a virus or possibly a rootkit but it is still relatively safe to back up documents, music files etc. to external storage although ideally you'd be better off doing this from something like an ubuntu live cd or a bartpe cd to prevent any viruses you may have from installing themselves to your external storage. Viruses that can spread to the bios are still very rare so that's an outside possibility, your best bet is to reinstall from your original xp cd or system restore disk then install a virus checker and apply all your windows updates and not until you've done all that plug in your external storage virus check your files then copy them back to your PC.

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Perhaps I have a hardware problem. I have mislaid my Live CD so I tried installing Ubuntu on some unpartitioned space I had on my HD, but my PC still powers off randomly during this process. Going to open box and check everything is seated properly as a next step. Then not sure, maybe re-flash BIOS? I have tried choosing fail-safe defaults in BIOS already, but it had no effect. –  hollystyles Sep 1 '09 at 11:37
    
Sounds nasty, is it possible your pc is overheating? If it's a desktop it might be worth running it with the case off so you can check all the fans are running. If it's been running for a while you might want to get some compressed air and blow all the inevitable dust out of it. –  Col Sep 1 '09 at 12:23
    
Updated post, almost exhausted all avenues thinking mobo maybe ultimately prove to be fubar and this is just one of those things life throws at you now and then. –  hollystyles Sep 16 '09 at 9:03
    
I guess it happens, although it is unusual for it to be intermittent as you describe. I guess it could be either the PSU or the motherboard so if you have a spare PSU I'd try that before I spend any money. If you've installed any additional hardware it's possible you've reached your PSU's limit or as I said it could be a heat issue for the chipset on the motherboard or the CPU. –  Col Sep 16 '09 at 11:45

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