Replacing the Power Supply in Your Computer
Power supplies are a very common item to fail in a computer. Unless you have your computer plugged into a UPS or Uninterruptable Power Supply, your power supply work very hard absorbing small fluctuations in power, including protecting things inside from things like voltage drops and minor spikes and power flicker all things that happen in a normal power grid. This can present a lot of wear and tear on a power supply and as such they fail often and need to be replaced.
If you suspect your power supply might need to be replaced, first you can do a little preliminary testing. On some computers entering the BIOS can yield information about what voltages your computer is actually getting. Look for values of 3.3v+, 5.0v+ and 12v+ and ensure the voltages that your computer is reporting aren’t significantly higher or lower than these. Also you can buy a small tester should you suspect issues with your power supply. Additionally if you have problems starting your computer or it shuts off randomly, the power supply can be the culprit in some cases.
Inside your computer, your power supply is the large brick looking item with all the cables coming out of it. You can be certain it is correct by looking to see where you plug your power cable into. To remove it, simply unplug every cable that connects to it inside the case and unscrew 4 screws on the outside and slip it out. When you are ready to install your new one, start by carefully slipping it in, then replacing the 4 screws you removed from the back and plug all of your cables back in. Replace the computer and the cabling and start it up!