[CRASH] Random crashing mostly when I die, this only happens on League.

Ever since I started playing League, I would randomly crash when I die. I thought, "Huh. I wonder what this is." I kept on playing games everyday and now I'm at the point of a 20 minute leaverbuster, which has wasted hours of what could be possible games. I've been coping with this problem for 3 months, and I'm at the point of punching through my monitor screen. Furthermore, this only happens on League. Ever since the problem has been getting worse and I'm crashing more now, even when I'm alive. When I don't crash, I sometimes freeze for 14 seconds at a time. However, when I do crash, there is a variety of things that happen.

1. My screen freezes on the last frame and the last sound loops

2. I get a plain grey screen that will never go away unless I hard restart

3. I get colored or white or a variety of colored, thick, thoroughly colored rays going down my screen with the last sound looping

Furthermore, I can only fix this if I hard restart my computer. I have searched online many many times and I have discovered that many other people are having the same problems, its just that I have them more frequently.