Weird Issue while Gaming

Not really sure what the issue is, but its only happened twice, and only after I started playing Pragmata.

Basically what happens is about an hour or so into playing the game, my PC... doesn't quite freeze but all the inputs stop working. Headphones, keyboard, mouse, controller. None of it works. From my research, it looks like it could be a power supply issue, but Im not sure. The game is still running, nothing is frozen per se. But nothing can be inputted so I have to force a restart. Any ideas?