Computer Won't Turn On When CPU Has Power

Intel Core 2 quad q8200 quad core proces...
October 25, 2009 at 16:00:52
Specs: Windows XP
MoBo: ASUS P5Q Premium
Ram: 2X 1-gig sticks
GPU: nVidia GeForce GTX 280 (BFG TECH)
PSU: 650W (BFG TECH)

I recently bought a 650W power supply, new motherboard, and new processor. When there are power cords plugged into any pieces of hardware aside from the CPU, my computer turns on. When I have everything unplugged aside from my Motherboard and CPU, the computer does not turn on. I'm wondering if this issue would be a faulty motherboard or a faulty processor? Note: There is a very light gray-tinted circle around the center of the motherboard's processor pins; could that be damage to the pins? I'm positive I haven't spilt any thermal compound onto the pins, and that's what it looks like. Could this be a preexisting damage to my motherboard? And would this damage (Whatever sort of material it is) prevent me from turning my computer on when the processor is getting power?


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#1
October 25, 2009 at 18:26:32
When it comes on, does it post normally?

Sounds like it might be a bad ground. The ground is coming through one of the attached periipherals instead of the PC power supply. You might detach the peripherals one-by-one and see which one is causing it to work but I'll bet it's the monitor.

If you're using a power strip try connecting the PC directly to the wall socket and see if that makes a difference.

I want a star too! "I'm Good Enough, I'm Smart Enough, and Doggone It, People Like Me!"


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#2
October 26, 2009 at 13:38:58
I only got it to turn on one time, the first time I installed my new equipment. While I was installing my OS, the computer turned off and from that point on I could only get it to turn on when the processor power cord was unplugged. If anything, it sounds like my processor got fried from lack of cooling, but I had thermal paste properly placed on it and a new fan.

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#3
October 26, 2009 at 17:34:03
Not exactly sure what you mean by 'processor power cord'. The PC shouldn't come on at all if you pulled the AC power cord. Or do you mean the 4-wire motherboard connector (2 black wires and 2 yellow)?

It doesn't seem like it's a heat/thermal paste issue but can't say for sure.

I want a star too! "I'm Good Enough, I'm Smart Enough, and Doggone It, People Like Me!"


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Related Solutions

#4
October 27, 2009 at 12:02:01
Yes, i'm referring to the 4-pin power connector. Sorry if that caused some confusion.

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#5
October 27, 2009 at 20:33:52
Does your power supply have a 20 or 24-pin motherboard connection? The extra 4 pins doubles the current capacity on the 12 volt rail:

http://www.playtool.com/pages/psuco...

which may be necessary if you're using a PCI-E card. If you're not using a PCI-E card the PSU will not need to supply as much current at 12 volts and maybe the 4-pin power connection for the cpu won't be necessary. Still, even in that case attaching the 4-pin connector shouldn't cause a problem.

If it seems to work OK without the 4-pin connector attached then I guess leave it that way. If it's powering up but nothing is showing on the screen then that's something else---motherboard, cpu and/or power supply.

I want a star too! "I'm Good Enough, I'm Smart Enough, and Doggone It, People Like Me!"


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#6
November 2, 2009 at 15:18:43
It's a 24-pin connector and a PCI-E card.

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#7
November 2, 2009 at 16:29:14
Still not clear. Does the PC function normally when the 4-wire cable is not connected? If not what is the difference in its behavior when the cable is plugged in and when it's not?

Help me Jebus!


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#8
November 3, 2009 at 12:26:21
The PC starts up when the 4-pin connector that goes into the motherboard for the processor is NOT plugged in. When it is, the computer doesn't even start up for a split second.

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#9
November 3, 2009 at 19:17:07
Starts up and goes into windows OK or just powers up but nothing on the screen?

Help me Jebus!


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#10
November 4, 2009 at 18:32:46
Powers up with nothing on the screen.

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#11
November 4, 2009 at 19:39:01
Remove all cards except video and disconnect all the drives. If it seems to work OK then, the fault is with one of the disconnected or removed items. It it still doesn't work it could be PSU, motherboard and/or cpu. I know it doesn't help much but the symptoms don't point to a specific problem.

Help me Jebus!


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