Thanks Marty,
I did try that to but without success,  

If you followed the steps to unplug external boards, the result on the MPU is either working, or not working, then from there the next step was to re-plug in each external board until the MPU faulted (no leds etc).

If the MPU board alone (attached only to power supply) does not boot/flash leds then the your MPU is potentially stuffed, although you still need to prove ALL supplies on the power supply board are correct, 5volts, 12volts etc etc.
If power supply is wrong, MPU will never boot correctly for a start.
After confirming all that, then you'd look into corroded eprom sockets and so forth.

MM