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System is powering up, but no display whatsoever. No blinks/power on the keyboard. CPU, LAN Card, GPU are all up and running.

Beep - This feature was somehow disabled to fix the power button on Cabinet coolermaster CM-690.

The onboard lan card got bad and use to cause BSOD on Windows XP and numerous problems on Windows 7. So it was disabled and PCI Lan is in use. So after installing the LAN Card(Yesterday) the system booted up pretty well and both Windows XP and 7 ran pretty fine with no problems at all.

Now in the morning its refusing to wake up. It got started once but just after the initial boot screen, it went dead again(no power in keyboard, monitor but CPU, GPU and LAN were all on.

I am guessing maybe the Motherboard is the problem, or well there can be some issue with the start button.

Any ideas? Thanks.

EDIT: NO POST or OS Boot screens.

UPDATE: Came back from office couple of hours ago and the system is backup and running fine for 3 hours now. I think the PSU is bad. If there was problem with MOBO the system wouldn't have started.

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It could be the monitor, sometimes somethings happen suddenly , try testing your monitor and check for loose wires – subanki Sep 13 '10 at 7:31

No POST screen suggests something is wrong with the MOBO. Since you suggested you just replaced your LAN card, maybe it's not sitting on the MOB correctly, or else you knocked something out of place while replacing it.

I suggest taking the card out and trying to boot. If it still doesn't get to POST, check your memory and CPU placement first, before deciding you have a MOBO issue.

If you do get to POST, put the card back in securely and try booting again. If now it doesn't boot - you have a faulty card - or a faulty PCI connector.

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I disabled the onboard LAN(not PCI) since it was faulty and got a new PCI LAN. The system did boot up well after installing the LAN Card(PCI). – Aseem Gautam Sep 13 '10 at 10:45
Take out the PCI Nic. Malfunctioning PCI cards can cause unusual problems. – chunkyb2002 Sep 13 '10 at 11:09
Yeah, take out all expansion cards and see if it will POST. If that doesn't work take out all the RAM too - it shouldn't POST like that but it should beep like crazy if the board is working correctly, and that'll tell you you either have a bad DIMM or a bad slot. – Shinrai Sep 13 '10 at 14:38

If you're seeing the POST and OS boot screens but it goes blank it suggests a problem with the graphics driver. Hitting f8 during the boot sequence and selecting VGA mode in windows XP or Low resolution mode in windows 7 will let you uninstall the graphics drivers to reinstall.

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NO POST or OS Boot screens. – Aseem Gautam Sep 13 '10 at 9:10
That's most probably motherboard then. +1'd the answer above. – chunkyb2002 Sep 13 '10 at 11:07

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