My PC froze completely while I was watching a movie, so I held the power button to shut it down. Since then, it powers on with the fans spinning but never shows a display or completes POST.
System specs:
- CPU: AMD Ryzen 9 7900X3D
- Motherboard: ASUS Prime B650-PLUS WIFI
- GPU: XFX Radeon RX 7900 XTX
- Memory: 64GB DDR5 in two 32GB sticks
- PSU: Corsair RM850x
- Built in February 2024
I left the system unplugged overnight, removed the graphics card, tried both HDMI and DisplayPort from the motherboard, tested different RAM configurations including no RAM, and cleared the CMOS using both the CLRTC pins and by removing the battery. I also removed the components from the case and tested the motherboard outside the case with only the CPU installed. The fans still spin, but there is no display or obvious diagnostic indicator.
The motherboard does not appear to have conventional POST LEDs or a speaker. Is there anything else I should check before taking it to a repair shop, and how can I determine whether the motherboard, CPU, RAM, GPU, or power supply has failed?
3 Answers
Reseat and verify every power connection, especially the 24-pin motherboard cable and the 8-pin CPU/EPS cable near the processor. Make sure the CPU cable is not accidentally replaced with a PCIe cable. Then test with the motherboard on a nonconductive surface, one RAM stick in the recommended slot, and no drives or USB devices connected. Since the 7900X3D has integrated graphics, leave the GPU removed and connect the monitor to the motherboard output while testing.
Check the motherboard’s Q-LED Core feature. On this model, POST errors can be reported through the case power LED rather than dedicated motherboard lights. Connect the case power-switch LED according to the manual and watch its blink pattern while starting the system. The pattern should indicate whether the problem is CPU/DRAM, graphics, or the boot device. Also give DDR5 memory training several minutes after clearing CMOS before powering it off again.
The PSU is still a possible failure even if its fan or the system fans spin. A basic paperclip test only shows that it can turn on; it does not prove that the voltage stays stable under load. If the Q-LED code points nowhere or the system remains completely unresponsive, try a known-good compatible PSU, or have a shop test the PSU, motherboard, CPU, and memory individually. Do not reuse modular cables from another power supply.
The diagnostic behavior is easy to miss because it uses the case power LED. The motherboard specifications list Q-LED Core even though there are no normal onboard Q-LED indicators.