Is the screen clipping or are you seeing black sidebars in the game? Or is the monitor going completely black? If the monitor is going completely black, it could be entering a power save mode and something is wrong with it. If there are black sidebars while you're playing the game, it means that your screen resolution is too high for the game or that the resolution is not set right under the game settings.
If the game is clipping off the screen it means your monitor needs to be calibrated. To calibrate the monitor you can usually use the buttons on the monitor to accomplish this.