PC turns off randomly

[lleemon]

I built my pc around 2/2008 and has been working pretty good until recently. Things first started acting weird (by that I mean shutting down) when my son would watch Thomas and friends videos. Now it just seems to happen randomly where my pc just turns off. The latest was when I was using Dreamweaver I was downloading a larger file. No, it's usually not predictable but the following was.

I downloaded Ultimate Bood CD and ran the CPU Burn-in V1.00 test and both times it turned off at 160000.

Is it possible my CPU is bad? Or any thoughts on what else it could be or try to help determine the issue?

Thanks in advance.


PC specs:
Apevia X-Plorer Black w/ Clr Side
Intel Core 2 Quad Q6600 2.4Ghz 4x2mb 1066FSB CPU
XFX nForce 680i LT SLI Socket 775 Motherboard
Ultra X-Finity EE 600w PSU w/APFC
XFX GeForce 8600 GT 512MB PCIe w/DVI/TV-OUT
OCZ SLI 4096MB PC6400 DDR2 800MHz (2x2048MB) --NOTE ONLY USING 1 of the 2
LITE-ON 20x DVDRW SATA Litescribe Black
Microsoft Windows XP Pro SP3

[JPMiller]

My vote is for that garbage power supply dying...
Random restarts and shutdowns are most commonly power related anyway

[lleemon]

Any suggestions on a better power supply to look for? Is there a way to test to see if that is it?

[Kellie Dobbie]

Checking power supply voltage

You should unplug the system from the electrical outlet before testing the motherboard power. The ATX motherboard power connector uses a single P1 connector. This connector is keyed to prevent it from being inserted backwards. Power supplies supply power to the system board at the 12-volt, 5-volt, and 3.3-volt levels.

Using your multimeter on an ATX power supply, the purple wire should have 5V DC (Volts of DC power) flowing through it anytime the PC is plugged in. This should be the case whether the main power switch is turned on or off.

Once you’ve tested the purple wire (5V DC), test the voltage on the various 12-VDC circuits. You might have noticed that there are several black and several yellow wires on the P1 connector. The yellow wires indicate 12-VDC circuits. To test these circuits, set your multimeter to the 15-VDC or 20-VDC range (depending on what your individual multimeter uses). Next, with the PC powered on, place the red probe onto a yellow wire on the P1 connector and then place the black probe onto a black wire. Because the PC must be powered on, the P1 connector must be connected to the system board.

Once the probes are connected, your multimeter should indicate a voltage between 11 and 13 VDC. If a power supply is slowly dying and causing the types of problems that I described earlier, the voltage will be a little below this level. If you read a power level between 10.5 and 11 VDC, then your PC needs a new power supply. You may also notice voltage drops on the 5-VDC and 3.3-VDC circuits, but these voltage drops are smaller because you’re dealing with less power to begin with. Therefore, I recommend performing the tests on the 12-VDC circuits.

[JPMiller]

Yeah, nice cut and paste...

The best way to test is buy a GOOD PSU and replace it and if the issue stops, your done ... if not then you look at other likely suspects...
Namely the Motherboard, then CPU, and down the line...
I would begin by unplugging ANYTHING extra, Speakers, Dial up modems, usb devices, lan connection, even keyboard and mouse...
keep rebooting each time you disconnect something to test...

[lleemon]

Here is what I bought.
OCZ Technology 700W StealthXStream ATX Power Suppl

[JPMiller]

Good Choice...
Whats the verdict?

[lleemon]

Well, my original power supply must have known I was changing it because for about a week after I posted and bought the new power supply it didn't shut my pc down. Well, I finally got to it and changed it and ran that same test and this time it make it the whole way so either the hot days affect my old power supply or it was just buggy. Guess time will tell how this new power supply does.

Thanks for all that posted with advice.