connecting pc with my tv problem

anybody has experience with this?
Tried for 2 hours and it still doesn't work :'(

The sound worked immediately, no problem with that
but i don't get a screen on my television

two cables can provide the view:
an S-video cable and another one that gets in the yellow hole of my pc and tv
both are plugged in but no result


gfx card: nvidia geforce 6600 gt