How to replace the power supply
The power supply is the component that powers your device on your computer. This powers things like hard drives, CDROMs and CPUs. There may be times when you have to replace it.
Symptoms of a bad power supply can include random reboots, random computer crashes not starting at all.
When replacing your power supply, there are a number of things to consider. The most important thing to do is get the right one for your computer. Your computer will most likely use the ATX form factor. You also need to make sure you get a power supply with enough power for your computer hardware. 300-400 watts are sufficient for most computers. Make sure the power supply has enough power connections and the right type of connection.
Replacing the power supply is a very easy job. Make sure you unplug the power cord first! Then you can open the case and disconnect the power from the device and motherboard. Then you can take the four screws on the back of the outer case and pull the power supply from the inside. To install a new one just do the opposite.