Hello, I recently purchased a new Mobo (Gigabyte GA-P67A-D3-B3), CPU (i5 2500k), and RAM. I put it all together with my existing components, however when I power it up, it runs for .5 seconds, then seems to power down, I've stripped away components one by one, and seem to be getting the same result with only the Mobo,CPU and PSU. I've worked through a few checklists (including Tom's) and tried everything, but I'm still getting the same results. Any suggestions?