S-video TV hookup stuck in black and white

[fustercluck]

Having no luck troubleshooting (whatever that means) this one, usually when it's stuck in black and white it's just a loose cable somewhere, but I can't get any color to show up on my TV...when hooked up to my computer that is. The TV doesn't have trouble displaying colors from other sources.

Connection is s-video. Using an hd4870 video card.

Probably something small I'm forgetting. Any ideas?

 

[WildW]

The things to check when using s-video:

Make sure you're connected to an S-video capable input on the TV - not all are
Make sure you've selected the s-video input on the TV. Some sets will have separate AV channels for the same physical input socket, one for composite video, one for s-video, etc.
Make sure you've selected the right output format in your graphics card properties - e.g. NTSC for the USA, PAL for the UK, etc.