Laptop LCD problems?

[Praey]

I don't know much about laptops since this is my first one. I was just trying out the Warhammer 40,000: Dawn of War demo and had to alt+tab for one reason or another. When alt+tabbed back to the game, before I saw anything my screen went black and began to fade to white. When it finally became white after 10 seconds or so there were also black lines visible across the screen at even intervals. I hit a few buttons but decided there wasn't really any way that my screen was going to revert back to normal so I did a manual shutdown.

This has happened a few times in the past, though I'm not sure of the situations and circumstances before. Does anyone know what this is, what it means or what causes it to occur? I'm clueless.

Thanks.