Alienware R3 Freezes and Am Forced to Shut Down

Hello everyone, I am a pretty big gamer here, and when I play certain games, the game freezes and applications such as discord and or Skype freeze as well. Then the computer locks up and I am forced to hold the power button and restart. The games that I have experienced this with so far are Rocket League, Player Unknown Battlegrounds, and Black Desert. I have just ran two test through Dell's Support Assist and both my Graphics Card and Processor passed. I am not sure what is causing this.