This document pertains to HP and Compaq desktop computers.
Power supply problems can easily be mistaken for other startup issues. Before assuming the power supply is at fault, it is important to first find out why there is no power, then you can correct the problem. To diagnose the problem, plug a grounded power cord from the computer into a grounded power outlet. Once the cable is connected, press the power button on the front of the computer and look at the small light (LED) and fan on the power supply at the back of the computer. Use one of the following links that matches what you see and hear.
note:The Power Supply LED is not available on all the desktop computer models.
Figure : Power supply light
If the small light on the power supply does not turn on and the fan in the power supply does not spin, and it looks like there is no power, see Power supply light does not turn on.
If the small light on the power supply turns on, see Power supply light on or flashes.
If the lights on the computer come on or the power supply fan spins, see one of the following documents.