I have a Dell Dimension 8400 which recently shut down for no reason. The power switch had a solid amber light instead of the usual green. After disconnecting the power cord and reconnecting it some time later, the computer started up with no problems. A week later, the same thing happened only this time the amber light was blinking. I opened the tower and removed the power supply only to find the 4 pin, 12 volt connector between the motherboard and the PSU to be burned. I tested the power supply by jumping the green wire and a black wire on the 24 pin connector of the power supply and reading the output voltage on the 4 pin connector. The fan works properly and the voltage output is a steady 11.75 vdc. It seems to be working; however, there is no load on it during this process. Does anybody know what might be wrong with my computer? Is my power supply bad or am I in the market for a new motherboard? Any help would be greatly appreciated!