For months now, my screen has been messed up. Every time I try to play a game (ex.Minecraft or Warframe on steam) My screen gets derpy. After about 2-5 mins of playing i get horizontal black lines through my screen and is not limited to the game only. After those start, certain parts of my screen move to different places. Then my screen completely blacks out and my computer shuts down. Sometimes this even happens on youtube vids. I have a ATI Radeon HD 4200 graphics card.