strange pc turning off problem

[xirokx]

Hi there,

I replaced a like for like mobo in my friends system.

When I turn it on, the pc posts then when after the post screen the system just automatically switches itself off.

I have checked all connections, reseated RAM, reset CMOS, everything I can think off, I have even tried a diff psu...

I am running out of things to check, can someone please help?

thanks in advance..

 

[xirokx]

there is only 1 stick of RAM...

i double checked the cpu and the hsf...

i noted whilst the topside of the cpu had paste on it the bottom of the hsf did not, does that suggest to you it is not making contact?

hsf is plugged in correctly as the fan spins