PC turns on for a split second...

[Lukegblunt]

Hi, I've been using my PC I built for almost a year now and have had no problems with it. However I left it on over night which is normally and when I woke up it had shut itself off.
Ever since when I push the power button it turns on for a split second then turns off and back on again and off constantly without pushing anything.

First of all I though it might be the PSU, so I tested it with a power supply tester and everything is fine, everything is as it should be.

I then tested the GPU in another build and it's fine

I reseated all the RAM and still nothing

I have rest the CMOS and nothing

Any advise would be great. My specs are
intel i7 5820k
Asus X99 Duluxe
Gtx 980ti Hall of Fame edition
Corsair H1000i

 

[maxwellmelon]

still could be a bad psu. as I'm assuming you only did the paperclip test which does not test the psu under load.

also what PSU do you have? (what protection features is what I'm wondering)

have you tried just motherboard, one stick of ram everything else disconnected from motherboard and psu?

 

[xDeuiii]

Could be overheating issues. Tried resetting the heatsink PROPERLY with new thermal paste assuming you know how to do it.

 

[Lukegblunt]

No I didn't I used a PSU tester I got from Amazon to check the voltages and all was fine.

I have also tried just the motherboard

 

[Kjeld_]

i hade the same and it whas a defect in my bios so lets just say bad motherboard

 

[panathas]

It's probably the motherboard or the PSU. The only way to be 100% certain that it's not the PSU is to try another one that you know it's OK. Try to borrow one for a friend or try to use your PSU in another system and see what happens. PSU testers aren't reliable at all. A PSU that works with a tester and doesn't report abnormal voltages, doesn't mean that it's capable to turn on a system. It seems that some protection mechanism (motherboard or PSU) is turning on when you power your system and it shut's it down in order to prevent further damage.

Also try to disconnect everything from the PSU in order or rule out a short in some device, for example a shorted or fried Hard Disk/SSD/RAM/Fan could cause that behaviour. You could try to turn on your system without RAM,VGA,FANS,Hard Disks,SSD to see what happens. If it doesn't shut down, you board and your PSU are OK and one of your above devices is probably fried.

 

[Lukegblunt]

Ok, here's an update!
I tried my PC again and it is now everything is running. However, I've got nothing on screen and the error code 00 on my x99 deluxe.
I have took everything out of the case and rebuilt it part by part but still no luck!