My old Nvidea card had a TV-out on it. I thought it would be really cool when I bought it but then the first time I hooked it up I realized how lousy TVs really are (its probably better with the new 1080 TVs). Are you hooking it up with the right cables? Don't forget to let Windows know its outputting to a TV. Go to Settings -> Advanced and change your monitor to TV.
Good luck (both in getting it to work and not having anyone complain about posting it!)