What is happening is if I play Minecraft in fullscreen mode for too long, my computer will suddenly, with out warning go completely blank. The computer sounds like it is still on and running fine, but I cannot get a response out of it, nor can I see anything. In order to reboot properly after this happens I have to power off my PC, switch it off at the back, switch it back on again and boot it back up again.
This did happen before, but it happened with other games, and much quicker. I took it to a repair shop and they said it was a graphics card problem, and replaced my graphics card, and now it is happening again. However as far as I am aware it is only happening with Minecraft.
Have I got some setting which is allocating too much power to minecraft? I am not sure how much memory I have allocated to java, but I have 8GB of RAM, so that shouldn't be a problem, right?