Acer 24" LED Monitor switches to sleep mode after game

"All I was able to find after a quick google search is this semi relevant thread in a Minecraft Forum that suggests updating graphics drivers, and this ancient Virtual Dr. troubleshooting thread that has some potentially relevant stuff to try.

Hopefully this is a helpful start! If not, let us know some specifics about your system: graphics card, RAM, processor etc, so we have more to work with. Good luck!"