What Should You Do?
Before you go out and purchase another motherboard or CPU, there are a few things you can try. If your computer continues to turn off and on, it may not mean that your CPU is bad, but that it may be overheating. There are a lot of things that can cause this, including dust buildup on your computer's fans or the temperature of the room in which your computer is located.
An immediate solution is to remove the side panel of your computer case to allow cool air inside. Depending on the placement of the PC, placing a small fan near the case can also help to cool it. This obviously isn't ideal, however, so you'll want to find a better solution (such as moving your PC or buying a case with better airflow) quickly. If your computer still overheats after this step, there may be a problem with the processor heatsink.
The best way to determine a motherboard's error is to listen for the type of beep code that happens during POST. If you know the manufacturer of your motherboard, check their website to determine what BIOS is being used; this will help you better identify what the beep codes mean. If the computer does not POST, your motherboard may be down for the count, but make sure that the mobo is receiving power and that no components are improperly secured before throwing in the towel.
In the event that diagnosing and testing does not help, you may need to purchase a new motherboard. Be sure that you know about your current system set up so that you do not run into issues when you receive your new board.
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