Random crashes on recently bought (USED) PC.

So I recently bought a USED PC locally. Checked everything. Everything seemed fine. Checked details on CPU-Z, GPU-Z and temps were fine too on HWInfo. Even did some benchmarks.

Got it home, disassembled it, cleaned it and did a fresh install of Windows.

But been getting a few random crashes while gaming. Sometimes blue screen of death, other times Valorant/GTA crash to windows or a blank screen.

Could this be a hardware issue? Any way to make sure it's not a hardware problem? Or is it just some bugs in the games? Could this be due to the fresh install? Could it be the relatively cheap PSU?

Have been using it only for 2 days so not sure if there is any pattern. The games run at a high fps normally and the temps are normal too.

Please Help!

Specs : Ryzen 7 2700, RTX 2080, 8gbx2 3200 RAM, Cooler master lite 600w 80+ white PSU.