Or another CPU to test on the board, I imagine.
Check the power supply connections to the board. Also, the PS may have failed, another you can test with?
Check the CPU cooler, is it to tight or has moved? What CPU cooler do you have? Does it look evenly level on the CPU, and not tilting in one direction?
You may need to remove the CPU cooler and remove the CPU and check for bent contacts in the socket.