Screen randomly goes blank, must re-boot

I have recently installed Windows 8 Pro on my PC, which is a Gateway FX, with a Dell 23" LED monitor. For the most part, everything is fine. On occasion, however, the screen goes completely blank, and there is nothing I can do to "wake it up". I have tried Ctrl-Alt-Del, the Windows key, right and left clicking the mouse, and nothing works. In order to get the screen to work again, I have to...