What could cause random freezing on Windows 8.1?

[Danoded]

This happens on a 3.5" HDD and an M.2 NVMe SSD (970 EVO).

Freezing can happen right around boot, or an hour afterwards, not doing anything intensive, it just freezes. No overclocks on GPU/CPU, ran memtest on my RAM with XMP2 Profile no errors after over 1hr 30mins. No crash occurs, have to restart Windows physically in order to get a working system again.

 

[vapour]

try to reinstall OS,
all pc specs pls and what psu specifically?