I NEED HELP (grey screen)

I have played the game for sometime now, but recently i can not play anymore. Every game i join i am faced with a grey screen that occurs at random times in the middle of the game and sometime i am forced to restart my computer entirely. This if very aggravating since once i get back into the game odds are the game is over due to ff. I've tried searching for sometime now but have found no answers to fix this problem.