When you install the card you will have to install the drivers with a monitor plugged in. When this is done then you can enable the s-video/composite output. My experience is that it doesn't care if a monitor is plugged in or not. You can then use your TV as a monitor. A warning though...your resolution will not be good. Standard TV resolution is less than VGA (640x480). Somewhere around 512x320. Some of the newer video cards will let you output higher resolutions but that will only increase how much you can see. Last comments is to use s-video. It is a lot better than composite.
I was considering building my own media center pc, but I realized that my 27'' Sony CRT TV doesn't have any vga or dvi connections. But it does have s-video and composite connections.
Is it possible to have a s-video or composite connection as the computer's only display?
*Note: I will be buying a separate graphics card that has s-video or composite.