A lot more details would be helpful... like the model of motherboard and PSU, detailed specs like RAM amt, ddr type, graphics card model etc.
but from what I gathered so far its a possibility of a RAM issue. Open tase manager, select RAM and see how much is allocated to system reserved. (shouldn't be more than 1 GB)
You can also check in event viewer, in system tab and see for any errors regarding the freezing.
I recently built my own custom pc with Ryzen 2700k, however since the start it freezes randomly. I have changed the Motherboard, graphic card, SSD and power supply and it is none of them. I am really clue-less.
Settings for CPU on motherboard are all stock, so voltages etc are all on automatic and they are in sensible range. Even when I don't use XMP profile for my RAM it freezes so it shouldn't be ram either..
What happens is: it randomly freezes in applications like league of legends or firefox. It also happens more often when I use VPN, the application doesn't matter, I tested windows built in and vyperVPN. Also when I don't login into windows it also ALWAYS freezes. For example if I go eat something ~30 minutes.
The kind of freeze: Just screen freeze, no hanging sounds/ no sound at all. I don't get a BSOD too so I can't debug it.
System specs: https://valid.x86.fr/1zp1lg
I hope someone has more experience about these kind of problems.