My PC has been randomly freezing and restarting for a while. It started mostly during games, but now it happens more often regardless of what I'm doing—even when the system is idle. Strangely, running a game sometimes seems to prevent it. The screen freezes, goes black, and then I'm returned to the Windows lock screen without seeing a blue screen or error message. Temperatures look normal, I've cleaned out the dust and reapplied thermal paste, and I recently replaced the older power supply with a better one. Windows Memory Diagnostic also reported no problems. Could this be caused by the GPU or RAM, and what troubleshooting steps can I try before replacing expensive components?
2 Answers
Overheating is one possibility, but since your temperatures remain normal and you’ve already cleaned the system and replaced the thermal paste, it’s not the first thing I’d suspect. Check Windows Event Viewer around the time of each restart for critical errors, especially unexpected shutdown or hardware-related entries. Also try running a more thorough memory test, such as MemTest86, because Windows Memory Diagnostic can miss intermittent RAM problems. If you have multiple sticks, test them one at a time and try different motherboard slots.
Because there’s no blue screen, Windows may be losing power or the graphics driver may be crashing before it can display an error. Make sure automatic restart is disabled so a hidden stop error doesn’t disappear, and check whether crash dumps are being created in the Windows Minidump folder. Updating or clean-installing the GPU driver is also worth trying. If possible, test with integrated graphics or another GPU to help isolate the problem.
I’ll check Event Viewer and test each memory stick separately. The built-in memory test didn’t find anything, but I didn’t try a longer test.