New build only starts for 1 second (not faulty psu)

[Guest]

Hi,

Just built a new pc and all wired up correctly and built correctly and I press the on button and it starts for 1 second then cuts out. It is definitely not the psu as I have tried an old 400w one and my new 600w corsair one and the same thing happens!

Any ideas as this is really frustrating me!

 

[sadams04]

You have confirmed that you are supplying power to the motherboard via the 24pin plug AND power to the CPU via the 8-pin plug?

 

[natseb]

+1 for sadams04