My PC was working normally earlier today, but after shutting it down and turning it back on later, it stopped reaching POST. The fans spin, but the monitor stays blank and neither the keyboard nor mouse lights up. The case LED stays solid orange instead of blinking normally. I already cleared CMOS, reseated all four RAM modules, reseated the CPU, and disconnected and reconnected the main components and cables, but nothing changed. The system uses an Intel i3 4th-generation CPU, an ASRock B85M Pro4 motherboard, 12GB of RAM made up of two 2GB and two 4GB modules, a 450W PSU, and integrated graphics. What else should I test before replacing parts or taking it to a repair shop?
4 Answers
Try powering it on with no RAM installed. A functioning board and CPU should usually report a memory error through beeps or diagnostic indicators. If there is no error response at all, test with a known-good power supply. If every RAM stick fails individually and the system still cannot POST, the motherboard or CPU may have failed.
Start with the minimum possible configuration: CPU and cooler, motherboard, PSU, monitor, and a single RAM stick. Test each module separately and try the recommended single-stick slot from the motherboard manual. Also reseat the 24-pin motherboard cable and the CPU power connector. Mixed RAM kits can sometimes cause problems, even if they worked previously.
Because the fans spin, it’s easy to assume the power supply is fine, but that only confirms it is providing some power. A failing PSU can still prevent startup. If minimal-hardware testing and individual RAM checks do not help, try a known-good PSU before concluding that the motherboard or CPU needs replacement.
Disconnect every storage drive and any unnecessary USB or expansion device, then try the bare-minimum setup again. A failing drive or shorted peripheral can sometimes prevent POST before the BIOS screen appears. If it starts after the drives are removed, reconnect them one at a time to identify the problem.
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