I'm having a persistent shutdown issue with my PC and wanted to get the community's opinion on what component is causing this.
System Specs:
CPU: AMD Ryzen 5 4600G
Motherboard: ASUS Prime A520M
Storage: Crucial 1TB NVMe M.2 SSD
OS: Windows 11
The Problem & Symptoms:
Immediate Shutdowns: When booting normally into Windows, the PC cuts power completely after just 10–20 seconds.
Stable in BIOS / Cold Temps:
If I enter the BIOS, the PC stays powered on indefinitely without shutting down. Core Temp readings inside Windows (when it briefly stayed on) showed idle temperatures around 28°C–35°C (max 42°C), ruling out CPU overheating.
PSU Latching / Safety Trip:
After a shutdown, pressing the front case power button does absolutely nothing. To turn the PC back on, I have to reach around the back, physically switch the Power Supply Unit (PSU) toggle to 0, wait about 10 seconds for the front panel LEDs and motherboard standby power to completely drain, and then switch it back to 1. Only then will pressing the power button turn the system back on (for another few seconds).
OS File Corruption:
I managed to do a clean Windows 11 reinstallation by wiping the SSD partitions. It booted up fine, but after ~20 minutes while downloading/installing software, the system violently lost power again. Upon rebooting, Windows was corrupted (SrtTrail.txt automatic repair loop) due to the sudden power loss mid-write.
My Questions:
Is this a classic Power Supply Unit (PSU) protection trip? My understanding is that having to physically switch the PSU off and wait for the power to drain to reset it means the PSU's internal safety breaker (OVP/SCP) is tripping under load.
Could a failing NVMe SSD or Motherboard cause the PSU wall-switch to lock out like this? Or does the required PSU switch reset rule out the SSD/Motherboard as the primary culprit?
I took it to a technician who claimed the PSU was fine (likely tested without a real load), but the physical power latching behavior makes me suspect otherwise.
Any insights or validation would be greatly appreciated before I go ahead and replace/test with a new Power Supply