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System won't boot; power fails everything dies.

idsrvit asked
Last February or so I upgraded my computer with some new components. New power supply, new motherboard and RAM. New OS: win 7. About a week ago I clicked the mouse to bring the computer out of sleep mode: business as usual. Just after it booted up, maybe thirty seconds, the computer shut down, as in shut off. I waited half a minute and booted up. No go. I unplugged the power and back in and rebooted. No go. After about 2 minutes I tried again and it boot up.
Last night pretty much the same thing happened. Only this time it doesn't boot up at all. It tried and got about half way through BIOS and died. Normally, the KVM switch LED remains on. Now, nothing. I tried just a bit ago and there was the sound of a start up in the case and then nothing: no lights, nothing.

So, how do I troubleshoot this seeming hardware problem? Is it the power supply or the motherboard? How to tell without replacing anything.

Motherboard: ASUS M4A87TD EVO
Power Supply: PC Power and Cooling Silencer Mk II 950W

Thanks in advance. Robin
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Dr. KlahnPrincipal Software Engineer

The KVM LED not being lit is indicative of a power supply problem.  Try swapping the old power supply back in and see if the problem is alleviated.

Symptoms are consistent with a faulty capacitor in the power supply. Try another power supply as DrKlahn suggested.

Yes, probably the powersupply. Here's how to test it without changing:

I might be tempted to give it a good clean beforehand.  These things have a horrible tendancy to collect dust and increase the heat.

Distinguished Expert 2019

it looksd like the power supply is candidate #1, but there can be others ; use my guide to troubleshoot :
http://www.experts-exchange.com/Hardware/Components/Motherboards/A_1945.html                  (Short-overview-of-how-to-troubleshoot-bad-hardware-when-a-pc-does-not-post)


Thanks for the site referral. It helped a lot. And yes, it was the power supply.

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