my gateway windows xp came with a short cord that uses a video cord (the yellow one ) how does this cord work and what does it do?

Feel free to ask questions

I'll take a stab in the dark here, I sort of doubt it came with Windows XP. It is probably a S-video connector to hook to a TV-Out port on your video card so you can hook your PC to a TV screen, but without knowing more about your machine, it'd be hard to say.

You'll need to provide more info about your Gatweay, I feel. A model number would be a good place to start. I'll move this to the hardware section also.