league of legends keeps crashing my computer

When ever I play lol I'll get halfway into a game and my computer will "detect a problem" and it will restart. This is really annoying because I keep getting 20 minute lower priority ques and I don't want a real punishment because of my computer. I love lol but I can't play if this keeps happening because I don't want to ruin other peoples times. I already dusted out my computer and also said if there is a problem take no action. please help!