Computer shuts itself off

Last night my computer randomly shut down when I was using it. I restarted it and it would almost load then turn itself off again. I opened the case and let it sit for about an hour with an external fan blowing on the motherboard. Restarted it again, it fully loaded but shut down after a minute. I use Vista Ultimate, and have the processor/memory gages set up in my side bar. Right before it shut down the last time i noticed that my CPU gage was fluctuating rapidly betweek 85 and 99%, then it shut down.

I built the computer 2 years ago, gigabyte motherboard 6300 processor, 2gb ram, all-in-wonder video card.

I put this in the hardware thread because I'm wondering if its thermal issues, so i figure something needs to be replaced. Maybe someone has experienced this too...

Any suggestion on why this just started happening and what I could do to fix?

This is my first post so if I left out information that is needed just let me know.

Thanks in advance!

 

The only thing I suggest is that because of the work the CPU had to do, it got very hot. When it happens again, put your hand in the computer and see if the inside of the computer is warm.

 

Update:

When I got home yesterday I started the computer, it ran for 10min with the CPU usage being 90%-100% the whole time, then powered down when i tried to run task manager to see what was causing the high spike.

I went to the store, picked up some new thermal paste, cleaned out the computer case, disassembled everything, cleaned the heatsink/fan/chip, reseated chip and pluged in running only the onboard video.

Oddity...

I had forgotten to plug in my 12v_ATX power cord to the motherboard upon reassembly, but it powered right up but I wasn't able to get video. After thinking for a few minutes i saw that i forgot to plug the cord in. I shut it down and attached the cord. The monitor would boot and i could get into BIOS but when i restarted started the computer with the 12V plugged in the CPU fan wouldn't do a complete revolution, it would rock back and forth and if i "helped" it to turn over it would spin a few times around on its own then settle back to rocking back and forth. I unplugged the 12v_ATX cable and the fan went back to working as normal.

Could the fan be the source of what was initially the problem? Maybe it wasn't spinning fast enough to adequately cool the CPU?

What should i do next? I want to boot up the computer to see how long it runs but without the fan i'm not going to do it.

Any suggestions would be greatly appreciated.

 

Hi J,

Just a little explanation:

Some motherboards will not power up with the 12V plug disconnected. Some have the 12V socket tied to the rest of the 12v line on the motherboard and will boot. You will always get cleaner 12V for the processor with the 12v plug plugged into the MB.

Good Luck, Jim

 

Jim -

I understand that. What i was pointing out by the 12V not being plugged in was the fan situation. The fan worked when it wasn't plugged in, but when i plugged it in the CPU fan wouldn't work. So I am wondering if that was the reason my computer was shutting off in the first place due to overheating. But is it a faulty fan or a PSU, or maybe none of the above...