Computer randomly shuts off / restarts

[McNemar01]

At random times, my computer has been shutting off, then restarting. Sometimes, it restarts continously other times it will actually load Windows 7 for a little bit. Then, it repeats the process. I have tested the RAM with memtest86 and windows memory diagnostic. I replaced the old RAM with new RAM. I tested both sets of memory. Memtest86 and windows memory diagnostic indicated no errors. I ran system file checker and checkdisk on the harddrive. Indicated there was something that Windows recovery couldn't fix. I swapped out my video card with a known good card. Problem still reoccured. I unnplugged everything but the CPU, PSU and the video card. Problem still repeated itself. I unplugged the video card and disconnected the case power switch to the motherboard and shorted the power pins to get the computer up and running. It would run for a few minutes then shut off. POST screen didn't indicate any problems. I do not have a case speaker. So, I don't know what sounds are being made during bootup. This computer I've had for almost four years now. This is the first time I've had any major problems with it. The HD was replaced about a year ago. I think I may have a short somewhere, but everything looks fine on the board. I even blew compressed air through the case to get rid of the dust. My other thoughts are my motherboard may be shot. I really don't know. Sometimes, the computer will run for hours before I run into the restarts. Othertimes, it might occur as soon as I turn the computer on.

Windows 7 64 Bit Home
Gigabyte EX58-UD3R Rev 1.0
Intel Core i7 920
6 GB DDR3 1600 G-Skill
Thermaltake 500W PSU
Galaxy Nvidia GT 240 1 GB
Western Digital 500GB HD

 

[McNemar01]

The PSU was swapped out today for the Thermaltake. The Thermaltake was bought new.

 

[Guest]

have you tried clearing the cmos? sounds like a defective motherboard to me, have you been monitoring your cpu temps? that might also be the problem.

 

[McNemar01]

I did clear the cmos. Symptoms didn't change. CPU temps were ranging from 60 to 90.

 

[McNemar01]

Two BSOD's I am getting
IRQL NOT LESS OR EQUAL TO STOP OxOOOOOOA
System Service Exception STOP OxOOOOOO3B

 

[Guest]

I did clear the cmos. Symptoms didn't change. CPU temps were ranging from 60 to 90.

those cpu temps look pretty high. did the only psu work? have you tried re-installing windows?

 

[McNemar01]

I tried two psu's. They both worked fine in another build. I did reinstall windows and updated the video drivers and the important updates. Startup repair does launch as an option sometimes when the computer boots up and I run it but it says it can't fix the problem automatically.

 

[Guest]

sounds like a faulty motherboard to me

 

[McNemar01]

Is there any surefire way to rule the motherboard as faulty?

 

[Guest]

search the internet for 2 hours and try everything you can. the best way is to swap everything out [power supply, video card, ram] and you have already done that. have you tried flashing a new bios?

 

[McNemar01]

I have looked up a lot of stuff regarding faulty motherboards, processors, ram and power supply. Without another motherboard to try the processor. I can't rule out the motherboard or processor. Overheating I don't think is the issue but could be. Bios I was worried about flashing due to the constant restarts when it goes into that cycle. Oddly though, my computer hasn't been acting up lately. I'm going to have to assume their was a piece of dust or something causing the motherboard to short. As I have yet to encounter any restarts, bsod's or shut downs in the past two days with over 8 hours of normal operation. If it does start again, I'm going to have to try flashing bios with an updated version. Thank you for your help. I will post again if the issues start reoccuring.

 

[McNemar01]

Best answer selected by McNemar01.

 

[McNemar01]

It turned out to be a virus.

 

[donny1963]

I've had the same thing happen to me, and figured out it was my thermalkake 500 Watt power supply was dying.
see what's going on is the system is working until the PSU starts to overload too easy and then loses it and restarts all over again.. i had 4 hard drives in it, and so what i did was disconnect 1 of the hard drives and restarted and sure enough it didn't shut down or restart..
So i figured out that the power supply was unable to keep up with the wattage and amps that was needed to feed that one extra hard drive,. now for a 2nd test i installed my Geforce 650 GTX which requires a PCI-E power cable connected to it because i uses a ton of watts..
so when i connected my PCI-E power chord to it, it would start for a second then shut down and restart and do that cycle over and over again.
So that was the problem..
Also Note: Don't buy thermaltake Power supplies, because they advertise lets say 500 Watt but the power supply really only puts out 400 + watts that's it..
they false advertise what your buying which in my opinion should be against the law to do, but i found atricles about it.

So any time your computer restarts (shuts down & restarts over again) that means your Power supply is failing or is not capable of putting out the power required..
a good new PSU would probably solve your problem...