Computer only remains on without 4 pin power cable for CPU

[solidberserker]

Machine only remains on without 4 pin cable for CPU power. I have tried 2 different PSU, I have disconnected GPU, tried different RAM sticks, and disconnected case fans. Each time time it powers on for a second then shuts down. If I disconnect the 4 pin cable for the CPU it stays on, even with all components connected. Same results with either PSU. Did I miss anything or is the CPU shot?

 

[clutchc]

The CPU is apparently getting its full +12V thru the 24 pin cable. That won't last long before it smokes. I would think the MB is bad for that to happen.