To install a new power supply, you don't have to send your computer to a specialist; you can install one yourself. Before You Purchase.
You can buy a new power supply from your computer's manufacturer, a computer store, or an independent manufacturer, but first you should examine your current power supply. Check to see if your power supply is AT (Advanced Technology) or ATX (Advanced Technology Extended) style. Your power supply should be labeled AT or ATX, and in the same area, you should see the output voltage in watts (for instance, ATX-250W). Be sure to buy a new power supply with the same or higher wattage as your old power supply. The higher the wattage, the more energy your power supply will provide to your computer. If you're adding additional components to your PC, you should purchase a higher wattage power supply. Furthermore, measure the dimensions of your old power supply, and make sure these measurements are the same as the new power supply you're going to purchase. Get Started.
To replace your old power supply, you'll need a Phillips or flathead screwdriver, a well-lit, low-static area (avoid carpeted areas), small containers (to hold screws or loose parts), and a pen and paper.
Turn off your computer and all the peripherals (such as your monitor, printer, modem, and scanner). Unplug your PC and all the peripherals from their outlets. After that, unplug all peripherals from the back of the computer. Move to a well-lit, static-free area, such as a tile floor or a kitchen table. Remove the computer case or panels to expose the interior of your PC. The power supply is enclosed in a metal box located in the corner of your computer case.
Before you disconnect any wires, be sure to sketch and/or note where and how each of the wires is connected. These notes will help you remember where to plug things in when you install your new power supply. In addition, when you remove any components from your PC, you should put any loose screws or loose parts in separate, labeled containers to keep them safe and organized.
Find the bundle of wires that come out of your power supply. These wires connect to your motherboard and various drives. Follow the wires to their white, plastic connectors and pull each connector until it is free (never pull directly on the wires). Remove all wires from their internal components. You may have to disconnect the on/off switch if the switch is not built onto the power supply. Occasionally, a large bracket secures a computer's power supply. To remove the bracket, loosen the screws and take it out. Now, remove the four screws closest to the outside edge of the computer case. Don't remove the screws that hold in the power supply fan. Carefully lift out your power supply (don't be afraid to pull it out with a little force).
To install your new power supply, you can reverse the actions you took to remove your old one. Put the new power supply in the same place as the old unit, tighten the perimeter screws into place, replace the bracket, and reconnect the on/off switch. Reconnect the wires by following your sketches and/or notes in reverse. If you have any loose wires, bind them together with a twist-tie. Make sure the voltage switch visible on the power supply is set at 120V (120 volts, common in the United States). Replace your computer case/panels. Connect all peripherals and the power cord to the back of your PC. Plug your PC and the peripherals into their respective outlets. Start It Up.
Turn on your computer and monitor. You should hear the normal sounds of a computer powering up, such as the fan and hard drive spinning. If your PC doesn't turn on or if any components in your system don't function, you should turn off your PC and unplug it. Remove the case and check to make sure all the wires are properly connected. Replace the case, plug in your computer, and turn it back on. If you continue to experience problems, contact the power supply's manufacturer or your PC's manufacturer.
Or you can see this :