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Earlier today, my computer spontaneously shut itself off and refused to turn back on. I tested my PSU and it's operating fine. I unplugged everything and let it sit for a while and it started to make a high pitched coil whine/hiss. When I came back an hour later and plugged in only the power cord, it turned on without any issues.

After some troubleshooting, I noticed my motherboard (Intel D975XBX2) has a red CPU led and VR led that come on whenever I plug my monitor into my graphics card via display port. DVI does not cause a similar issue. I was running three monitors off the card, so I need both DVI ports and the display port working.

Is it likely my graphics card needs to be replaced, or should I be looking elsewhere to resolve this issue?

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Are both LEDs turning on, or just the VR LED? BTW these LEDs are temperature warning indicators for the CPU and on-board voltage regulators. How loud was the "whine/hiss"? How long did it last? As a first guess, there may be a fault in the motherboard's local power circuitry. Maybe the cause is poor cooling. "Am I right to..." - No, and that's a pompous way to ask a question. –  sawdust Sep 12 '12 at 1:15
    
@sawdust Both LEDs turn on immediately when I plug in the cord, even if the computer is off. The hissing lasted 30-45 seconds and was audible across the room, but not super loud. Cooling should not be an issue. The room stays cool, and temps were fine last I checked a week ago. I also regularly blow out extra dust. Why would the display port exclusively be causing a problem if the mobo was bad? –  rllr Sep 12 '12 at 8:23
    
Seems like those LEDs have somekind of secondary indicator function besides temperature. Maybe you have to ask Intel. Re the hissing: unplug the PC, under a good light with a magnifying glass, inspect the printed circuit boards (e.g. mobo, GPU). Look for anything strange, a popped capacitor maybe? Assuming that the DisplayPort is on the GPU card, and that the GPU card is plugged into a PCI Express slot that should be unpowered when the PC is in standby (what you call "off"), then I have no idea why 2 "temperature" LEDs should turn red. –  sawdust Sep 12 '12 at 9:46
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So it turns out my displayport cable from monoprice was not made to spec.

Pin 20 was feeding 3.3v back into my graphics card when it should have no connection. This caused the warning indicators on the motherboard to light up. The spec clearly states:

3.2.2 DP_PWR Wire A standard DisplayPort cable must have no wire for the DP_PWR pin. Only captive cables supplied with cable powered Branch Devices or cables permanently attached to Sink Devices are permitted to have the wire for DP_PWR. These captive/attached cables must have a standard DisplayPort plug connector (as specified in Section 4.2.1) on one end only. The other end must either be permanently attached or have a custom connector.

Purchased a Belkin cable and this resolved the issue.

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