So here is the problem i am trying to hook my tv up as a monitor using a cable like this

and here is a picture of my video card it is a ati radeon video card
i have been googling for days now trying to get this to work. i plug the sevin pin svideo to rca adapter into the back of my graphics/video card, then i use the rca cord to plug into my tv and i get nothing just a black screen. the cord and cables all work fine on my laptop. i just dont know if im missing something or whats going on. please help!!!!!!!!!!!!!