My computer or the game?

Okay. At first, when this happened, i thought, "This just happened once, it won't happen again." And then it happened again. To where I just do one little thing and then the game just freezes on 2 frames, playing them over and over again, making a strange noise, and then after a minute, my whole computer crashes. And the only reason I can think of this happening is that my computer is a tad bit old, but it' really not that old. This has happened twice. The first time it wasn't a big deal, because my team could handle the 4v5. But the second time this happened, when i finally reconnected, we were losing terribly, and not only that but someone wanted to report me for leaving, as if i did it on purpose. And i feel like if this happens again, then I'll have a game suspension. For leaving the game when i really didn't want to. Please, if there is anything anyone can do, just tell me.