Laptop help

[chickfilafan]

i was using my laptop and watching tv and the screen went black. I thought it was just the screensaver or something because it's done it before. This time however when I pused a button or moved the mouse it did not go back. I could still hear sounds because my friend IMed me. I tried hooking it up to an external monitor but it didn't work. I might still have a warranty at Best buy but I am not sure. If I don't, what could it be? I'm not that computer savvy but could it be the video card since it won't work with another monitor?

 

[chickfilafan]

Here's an update, I let the laptop stay turned off for the night and tried it again this morning. It did work for a few minutes until i tried to open something then the screen went black.