PC hard-freezes after cold boot, fans stay on, USB/display die — PSU or motherboard?
My desktop has an intermittent failure where, after some time on, the monitor loses signal, keyboard/mouse lights turn off, and the system becomes completely unresponsive. The case fans and internal lights stay on.
It happens on both Windows and Linux, and it also happened while sitting in BIOS, so I’m assuming this is hardware-level.
Extra details:
- CapsLock becomes unresponsive.
- One time I've heard an USB disconnect sounds before it fails.
- The power button becomes unresponsive too, even holding it down.
- CPU and GPU temps look normal, around 30-40.
- GPU fans are spinning.
- I reseated the GPU and RAM. It seemed better for a while, but the issue came back.
- It is inconsistent: sometimes it fails after 10 minutes, sometimes it fails after 1 minute, but once it ran for a entire day and even survived 5 hours of gaming.
The desktop is close to 2 years old, the specs are:
- gpu: RTX 3060
- cpu: Ryzen 5 5600x
- ram: 2x8gb corsair vengeance lpx
- psu: corsair vs650
- moba: A520M-A PRO
I don’t have integrated graphics, so I can’t test without the GPU. I have spare RAM sticks and another PSU, but the spare PSU is older.
What could be happening? Since it's inconsistent, I don't know how to troubleshoot it correctly. Any suggestions or similar experiences?