Help! Periodic system reboots/file corruption, whats causing it?

[Nastya]

I've been running this computer for about 15mnths now with no stability issues at all... up until yesterday at least. Now I'm getting corrupted files on occasion and the system periodically reboots every 10-15min with no apparent cause.

Normally I'd expect it to be the PSU if the system is randomly rebooting, but the reboots will often happen when the system is just sitting at the desktop doing nothing yet run perfectly fine when heavily loaded, and removing hardware to lessen the load on the PSU doesn't seem to do anything to lessen the frequency of the reboots.
It does however consistently reboot whenever I download any Windows updates, delete items from the start menu, or try to delete my Outlook deleted items folder.

It's definitely not an issue with Windows, as I've formatted and reinstalled fresh a couple times now with no change.
Can't see it being either of the hard drives's because the problems are there regardless of which HDD Windows is installed on.

Replaced the DRAM, and graphics card and neither had any effect at all.


What could it be?
PSU?
Motherboard?
One or both of the Hard drive's?

Don't see how it could be anything else.


Specs:
Gigabyte GA-K8NF-9
Opteron 170
2GB DDR400
CDRW
DVDRW
2x HDD's (WD1200JB, WD3200AAKS)
Geforce 7900GS
400W Enermax PSU

I don't think I'm putting to much load on the PSU, and it's run fine for over a year now.

Suggestions for what to try? Right now I'm leaning toward buying a new PSU, and hoping that resolves the problems... the only other thing I think it really could be would be the motherboard... would it cause such issues?

Any assistance would be greatly appreciated.

 

[TC91]

is the computer overclocked in anyway? you could also check to see if the heatsink is properly mounted. it could also be a voltage problem, check the bios to see if the cpu is getting sufficient voltage. also check out cooling/airflow, it could be overheating or the heat may have taken its toll on either the motherboard/psu and to a much lesser extent, possibly the cpu. if you are using 4 sticks of ram, make sure the command rate is set to 2T instead of 1T. i dont think the psu is being overloaded, but if you had a spare one around to test, maybe see if that works. it may also be a driver problem, but since you said you already installed a fresh install of windows, i dont think that would be too likely.

 

[Nastya]

Not overclocked at all, everything in the BIOS is set pretty about as leniently as possible. CPU temp is about 40 degrees celsius at full load, so it shouldn't be a worry either.

 

[Blain]

* Are there any bulging or leaking caps on the MB?
* What exact model is the Enermax 400W PS?
* Do you have any sort of UPS or line conditioner on your power to the PC?

 

[MegaVovaN]

Sounds like a bad hard drive cable.

Try a different HDD cable or at least inspect current one visually to see if it's bent/folded too much...and reseat the plugs in motherboard and HDD.

 

[Nastya]

Originally posted by: MegaVovaN
Sounds like a bad hard drive cable.

Try a different HDD cable or at least inspect current one visually to see if it's bent/folded too much...and reseat the plugs in motherboard and HDD.

Both HDD's, acting up at the same time and/or both cables though?
Possible, but it seems unlikely. Still, I'm going to throw a different cable in there and remove both HDD's and toss in a different one and see if that helps.