Have my Tv hooked up on S-video output on my video card and when I start a full screen game the TV goes blank?

I want to have a full screen game on my monitor and a movie on my TV from the S-video but if I am playing a movie on my TV then start a full screen game the TV goes blank.Its weird a window can be open on the monitor and the tv works fine but its when you do anything full screen on the monitor the TV goes blank.

Thanks for any help|||In the game configuration set the screen resolution to match your TV. Check your video card's manual.|||That's just the way the video card works, you can't run a fullscreen video on the TV and a fullscreen game on your monitor - just the nature of the beast.