Computer won't start: fans and lights turn on for a second, then off right away

todospreston

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Jul 30, 2015
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Hi, I built a computer for my family about 4 years ago. Yesterday I opened it up to clean out all the dust, put it back together, was working fine in the evening, and then this morning wouldn't start. Every time I press the power button the motherboard lights and CPU fan turn on for a second, then turn off immediately (this actually happens twice each time I press the power button: once on/off when I push the button in, and once on/off when the button is released. If I hold the button down nothing happens).

I've already read several threads about similar problems. I've tried unplugging and replugging all of the power supply cables, CPU fan, RAM, graphics card, hard drives, and disc drive, with no luck. In most of the other threads it seems the PSU is most likely the problem--but I wanted to double check here to see if anyone else had any ideas. I don't have any spare PSUs or friends with spares, so I might try to take it to a repair shop to test it, or just buy one from Best Buy that I can return if it doesn't fix the problem.
 
Solution
You can test the PSU by yourself, bear in mind it is a little dangerous (and I take no responsibility for any possible harms). Take a paperclip, unwind it. Take the 24 pin plug and see where the green and black wires go. Put one end of the paperclip into the socket where the green wire goes and the other end into the socket where the black wire goes. Turn on the PSU and if the PSU fan spins then your PSU isn't the issue. (https://www.youtube.com/watch?v=5FWXgQSokF4)
Another thing, you want to try is taking the mobo out of the case. Attach only the 24 pin plug and the system fan. Switch on the PSU and see if the fan spins. If you have tested the PSU prior to this and it is functional then it's likely your motherboard is the issue. Let me...

todospreston

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Jul 30, 2015
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Yeah, the Corsair that I have only has a 3 year warranty; I checked with them anyways but they won't do anything. Thanks though!
 

syked3

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Jul 7, 2015
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You can test the PSU by yourself, bear in mind it is a little dangerous (and I take no responsibility for any possible harms). Take a paperclip, unwind it. Take the 24 pin plug and see where the green and black wires go. Put one end of the paperclip into the socket where the green wire goes and the other end into the socket where the black wire goes. Turn on the PSU and if the PSU fan spins then your PSU isn't the issue. (https://www.youtube.com/watch?v=5FWXgQSokF4)
Another thing, you want to try is taking the mobo out of the case. Attach only the 24 pin plug and the system fan. Switch on the PSU and see if the fan spins. If you have tested the PSU prior to this and it is functional then it's likely your motherboard is the issue. Let me know what happens
 
Solution

todospreston

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Jul 30, 2015
4
0
4,510


Thanks for the tip--I had heard of that trick before but never tried it. This time around I actually ended up just buying a new PSU and everything is working great.