Monitor loses signal or black screens while playing games
What may be happening is the video card isn't getting enough power or air circulation and is overheating/over stressed, therefore shutting down.
To test this, run a graphic taxing game like Sims 3 or 4. If the monitor looses signal or black screens frequently, it may be best to have it looked at. It could possibly mean that the power supply and/or video card needs to be replaced.
Note: This post has been locked as it's for informational purposes.