I built this PC about four months ago, and it worked normally until it suddenly stopped working roughly three weeks ago. Now it won't start at all: the AIO, motherboard, and RAM lighting turn on as soon as the power supply is switched on, but none of the fans spin. The case power button blinks at a steady rate, and pressing it does nothing.
Initially, the motherboard's CPU debug light was on. I tested the processor in another compatible system and confirmed that it had failed, so I replaced it. The CPU light is no longer illuminated, but the blinking power-button problem remains. I've already tried reseating the RAM, clearing the CMOS, removing the graphics card, and testing other basic configurations. I also replaced the power supply, but the symptoms did not change. What should I check next to narrow down the problem?
2 Answers
Since the lighting comes on, the board is receiving standby power, but that doesn’t necessarily mean it can start. Disconnect the case front-panel headers and briefly bridge the motherboard’s power-switch pins with a screwdriver. If it starts that way, the case button or its wiring is faulty. If nothing changes, test with only the motherboard, CPU and cooler, one RAM stick, and the power supply connected.
Double-check all of the power connections, especially the 24-pin motherboard cable, the CPU EPS cable, and any modular connections at the power supply. Unplug and firmly reseat each one. It’s also worth inspecting the CPU socket for bent pins or debris, since a socket issue can prevent startup even after replacing the processor. Remove the RAM and check both the modules and slots for dirt or damage before testing with one stick at a time.
The front-panel wiring was one of the first things I checked because of the blinking button, and it appears to be connected to the correct pins. I’ll still try starting it by bridging the power-switch pins directly.