How To Change Your Computer’s Power Supply
Upgrading your power supply is an excellent idea and one that you can easily do no matter your level of experience. You will especially want to upgrade your power supply when you have done any other upgrades to 
your machine like installing a new video card. So here are the steps to replacing your power supply.
Step one remove the power cord from the back of your computer. Next you need to find a good flat surface with sufficient light and no carpet underfoot. You will need a Phillips head screw driver for the job. You will see anywhere from four to maybe six screws there you need to unscrew the ones that hold the power supply to the outer case.
Now remove the side panel of your computer. You will easily be able to see the power supply, it opposite of where the hard drive and DVD drives are. Before you remove the power supply however you must remove the cables inside the computer. These power cable will go to devices such as your hard drive and DVD drive. There is also a power connector that goes to the mother board. Once all connections have been removed you can now unscrew the remaining screws that hold the power supply to the frame of the computer.
You can now slide out your old power supply unit. Gently slide the unit away from the back of the machine. Installing your new unit is exactly the reverse steps. Be sure to attach all power connections carefully.
