one thing of interest. you didnt state if your card is an ati or nvidia, but just for your info ati cards have a special mode called theater mode that when you play a movie, the secondary display (your TV in this case) will be resized so that it fits the whole screen. so you dont have to bother playing with the resolution, it will be perfect when playing the movies provided your TV is the secondary screen.

another thing, you mentioned composite, is your TV an LCD type? or the old Box type? cause some of hte more ciplak box types sometimes dont register when you hook up all the cables and try to et the output to ON.

once you've plugged in the TV, you can follow the following instructions :

1. open Control Panel
2. in Control Panel, switch to Classic View and open the option called Display
3. select the Settings tab
4. click the Advanced button
5. select the Display tab
6. if your TV has been detected by the GPU, the button called TV will have a power symbol highlighted in Red.
7. select that Red symbol, and it apply the settings.

your TV should show the same output as your monitor, though the resolution might be wrong. you can adjust the resolution like normal, or if you just plan to watch movies, make sure the Theater mode is on, its located in the Overlay tab.