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Step-by-Step: How to Install a New Power Supply

As you add beefy graphics boards and other energy-hungry upgrades, you can easily bring your stock power supply to its knees. If that happens, say hello to system crashes, the dreaded Blue Screen of Death, and sluggish performance in general.

To figure out whether your power supply can keep up with your planned upgrade, check out OuterVision eXtreme's excellent PSU Calculator. If you need more juice, take heart: Swapping in a new power supply is easier than you might think.

The majority of today's PCs use standard ATX power supplies. The important thing is to match the design you currently have. The online Power Supply Selector shows diagrams of different power-supply designs as you work through it, so you'll know what to buy.

When you've nailed that, shop for a supply that tops the suggested wattage by 50 or 100 watts so you'll have some room for future upgrades. Then, to install the power supply, follow these steps:

[1] Disconnect the main AC power cord.

[2] Open your case, and disconnect all of the power connectors. Trace all of the cables coming from the power supply to confirm that you haven't missed any.

[3] Unscrew the old power supply (see picture), slide it out, slide in the new supply, and screw it in.

[4] Reattach the power connectors.

[5] Check the voltage switch on the back of the power supply. It should be set to 110/115v.

[6] Reconnect the power cord, and you're juiced!