Why Power Button Doesn't Work

In rare cases, the power button itself breaks, so open the case and inspect the button for damage before trying anything else. If that isn’t the cause, then the motherboard may be fried due to electrical damage, but this problem most often happens after you install a hardware component and accidentally unseat the motherboard’s internal power plug from its socket. The size and shape of this socket (and sometimes there are two separate sockets) varies depending on the type and age of your motherboard, but the documentation that came with your computer should let you know where to look. You are looking for the power supply’s ATX (Advanced Technology Extended) plug, which has either 20 or 24 pins, and the ATX socket, which has an equal number of holes to accommodate the power pins. Some motherboards that have 20-pin ATX sockets also have a 4-pin ATX socket located elsewhere on the board, and both of these must be powered by separate cables for the motherboard to function. All you need to do is make sure the power plugs are fully seated in the sockets and the computer should boot.