New video card

My new video card is installed and running great. I am already seeing better performance on some programs and in Windows. I am going to ask to borrow my friends copy of Halo now that I have a graphics card that can handle it. I hooked my computer up to the tv. It worked but I won't be doing anything with it. You could not make out anything on the screen. Video and pictures worked fine. I tried to play a dvd. It worked on my monitor but not on the tv. Does anyone know how to fix that? I have InterVideo WinDVD Platinum.