System not posting for more than a second after new motherboard installed

[Aethosity1]

Hi guys,
So I recently decided to upgrade my PC with new motherboard, water cooler etc. Got it all assembled and the system turns on for a second, and then turns itself off again. So I'm thinking it's either the PSU, CPU or the new board. So I get the new mobo out of the case and run it with mobo power, RAM and CPU. The same thing happens.
I put the CPU back on the old board to identify whether or not it is, indeed, the new board and the PC powers on for a second, and then turns itself off again. This board has been in the system for over a year and has never had a problem. I've noticed that in the moment that the PC turns itself off on the original board, the CPU redlight is on. This suggests to me that I need a new CPU. What do you guys think?

System specs
New board: Gigabyte G1 990X
Old board: Asus m5a97 evo r2.0
CPU: FX6300
PSU: EVGA supernova 750 G2
GPU: EVGA GTX 980 SC
RAM: HyperX Fury 1866

 

[Vic 40]

Might want to check the cpu for bent pins.

 

[shood247]

Did u make sure to connect the 8 pin cpu power?

 

[Vic 40]

One thing else,you said you addded a new watercooler, did you use it checking with the old mobo as well? Made sure the connections are in the right place? Maybe check with the stock/old cooler as well.
Well read again and you also said you breadboarded the system so probably not,but can't hurt to ask or check.

 

[helpstar]

video card assembled as well while testing with the old board?

 

[Aethosity1]

I got the system to run on the old board using the watercooler. I ordered a replacement board that came today and exactly the same thing is happening - turns on for a second, turns itself off, then on again, then off. All subsequent times after the first boot, it turns on and off once

 

[Vic 40]

Can you try with just one ram stick? Try each slot and see if that makes it work.