Dead Motherboard or Cpu

[Bpeberhard]

To start I built my pc last year with these specs.1 Intel i3 4160 (might be slightly off, don't have original box) 2 Gigabyte h81m-s2ph 3 hyper x 8gb (1 stick) 4 Diablo tec 700w psu 5 pny 750ti. Later the GPU was changed to a 970, eventualy I wanted to upgrade my cpu. So i got a fx 6300 and 78lmt-usb3. I installed it with no io shield because it wasnt in the box reinstalled clean windows and it ran fine. I emailed the provider who sent me an io shield I removed the mother board and reinstalled with the io shield. It started to boot with display then it cut off and won't start now. I removed everything and put everything exactly the same on my old motherboard and cpu and it booted fine switched it all back to 78lmt-usb3 and fx 6300, no fan spin no post no boot. How can I tell if it's the mobo or cpu. I check to see if ohms ran through the mobo with a volt meter and it had conectitiviy but no post and no fan spin when I try to power on.

 

[Petrossa]

A mobo without an IO shield? That sounds a little dodgy for a new part, so I suspect you bought a used part.
The problem with used parts is that there is no guarantee that they will last any length of time. Maybe it was already faulty which is why it was sold?
More than likely it is the mobo as CPUs rarely die (Though AMD does tend to die a little more often than Intel does).
If you can lay your hands on another CPU, pop it onto that board to test with.