Recently, I had a client come to because his computer would not start up and he was not sure of the cause. After a quick inspection of the system I determined that it was the power supply had gone bad and needed to be replaced.

There are several symptoms that can occur when a power supply is not working or is not functioning properly, though in many situations there may be no warning before the power supply dies.

• Signs that the power supply is bad or not functioning properly:
• Machine does not boot or boots and beeps and then shuts back down.
• No power or lights turn on when pressing the power button.
• The fan(s) on the back of the power supply are not working (not spinning or are making noise). In many cases the power supply will still work with a noisy fan but it is usually a symptom that the power supply is close to failing.

Replacing a power supply is fairly straight forward process though if you don’t feel conformable working inside you computer I recommended bringing the machine to a repair shop.

The basic steps for replacing a power supply:

1. Unplug the computer.
2. Remove computer case cover.
3. Depending on the manufacturer the case will either slide off or require the removal of screws.
4. Record the connections from the power supply to the motherboard and components. Typically, there is at least on connection to the motherboard but there can be more. Then there is a connection to each device -CD, hard drive, DVD drive and floppy drive.
5. After recording the connections unplug all the devices from the power supply.
6. Next the power supply needs to be removed from the system. There are usually (depending on the model) a couple of screws on the back holding the power supply in place. In addition, there can be clips or screws inside the machine holding the power supply in place.
   
   Note: In order to make sure you get the correct replacement if you are not sure is to take the old power supply to a computer supply store and have them provide you with the replacement. If that is not possible contact the manufacturer of the machine directly to make sure the replacement is correct.
   
7. Place the new power supply in the machine and anchor back into place.
8. Re-connect the power supply to the motherboard and components.
9. Replace cover, plug-in and boot.

If all goes well you should be able to plug in the machine and, hopefully, have power and a working computer!