[Dear Vengeance]

My dad gave his old computer with a Radeon HD 5670 and every time I load up League of Legends it freezes and when I play halo it'll go to grey screen then come back. The fan works and the air is cool in there, it's not warm nor hot. Kinda getting mad now cause I can't play a full game. I've tried lowering the screen resolution and nothings working. Does anyone know whats happening? It'll also did the same thing when he had a GeForce GT 440.