In the past couple of months I have had to hard restart my pc around 10 times. I noticed every time my PC locks up its when I was in the middle of playing a game and shift+tab to bring up chat with friends. It does it very rarely and I can go one day with it not happening at all and another day it happened 3 times within a few hours.

Its not the same game either it has happened when playing multiple different games.
Anyone know how to fix this?