how could this issue possibly be anything outside software/game related?
Unless I misunderstanding the description of the problem OP is getting freezes when he contacts opponents in game immediately my mind goes to network Internet speed things of that nature but that wouldn't cause a computer to freeze but the fact of the game runs fine throughout the rest of everything else it rules out anything hardware based.... there's no bios update that resolves freezing while headshoting opponents
In what's close to three decades of computer experience I've never heard of an issue like this at least specifically like this ,I would like to see it ....upload a video of it please