Question System shuts down seconds after booting

[FAB577]

Hi all, I done some maintenance on my pc, new paste for the CPU and a good clean, I also changed the CMOS battery.

Put back together, then the system was shutting down after about 20mins of being on.

Took apart again today to ensure mobo wasn't shorting on anything and everything was securely plugged in (1 of my pins is broke on usb3 header but thought that surely wouldn't effect the booting?)

PSU is a Corsair HX1000i
Mobo is Asus Z97 gryphon armour edition

Any ideas?

View video of problem below:
https://linksharing.samsungcloud.com/lwaitb2urVzG

 

[popatim]

You've removed the CPU and checked to make sure no paste got under it & into the socket?
Where did the broken usb3 pin go to? Is it shorting out something in the case?

 

[FAB577]

Yep was the first thing I did, cleaned it off and re-pasted. I also re-seated the motherboard to ensure it was all ok.

I got the borken pin out.

I can't see anything that would cause a short, I've a feeling my PSU has gone, I've tried booting without GPU and still not even booting for 2 seconds