How do you know the power supply is the problem?
What issues are you experiencing?
Have you done any trouble shooting first? It could be a bad hard drive.
If you should need to replace the power supply first you need to get a replacement power supply for a gateway MFATXPNT ESX 500S - 300 watt power supply
you can get here.
The next step is to unplug the computer from the wall > remove the case side access panel > ground yourself with an Anti-Static wrist strap cord
so you don't fry *********** board electronics from static electricity discharge which can cost you a lot more to replace > now disconnect the plugs from the power supply wire harness, it may help to count the connections and mark them with a piece of tape or draw a diagram so you don't forget which loose cables should get reconnected to the new power supply. There will be at least one that connects directly to a plug on the mother board, DO NOT put tape there. > Next remove the screws which mount mount the power supply to the metal frame and slide out the power supply > slide the new power supply in the same way the other other was removed (note top from bottom) and then screw back to frame and reattach the cables > close the case > remove your grounded wrist band > plug computer back into wall and start the computer.
Congratulations, you have just replaced your power supply and ready to go. IMPORTANT:
Do not switch the power output selector switch on the power supply. Usually a recessed re switch which will adjust for european vs. US power input conversion.
Additional Resources and TutorialsStep by Step Video Tutorial to Replace Power SupplyWith pictures, step by stepDiagnosing ATX Power Supply Failure with DiagramHow to diagnose and replace a failed pc power supply
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