Video component cables - red, yellow, white compared to red, green, blue.

Hiya. My parents have got a swanky new tv that has the red, green and blue video component sockets the same as the DVD player. Right now they're just using the red, yellow, white (minus the red) and it looks ok. I was wondering if there would be any improvement in using a red, green and blue component cable. And also am I correct in thinking that that cable doesn't transmit sound, I'd need another cable for that?

And the red green and blue component cable is still analog, not digital, is that correct?

I've also got a seperate issue with an old Transonic DVD player. I had it connected with the red, yellow, white cable, and while fiddling with in the menu I inadvertently switched it over to S-video, and it went completely blank (because it's now in S-video). I don't have a tv that has S-video so I can't switch it back. There is no external reset button or anything like that. It's a long shot but I was wondering if I connected it with the red, green blue cable would I be able to access the menu again?

Thanks very much.

If your parents bought this shiny new FullHD 1080p TV, tell them if they're intelligent they'll dish out 100 bucks more and replace the DVD with a Blu-Ray player. Decent players upscale DVDs to the TV's resolution. This looks better than what a DVD-player can deliver. New players even come with solid media players for USB devices which support most media formats.
Until 1.5 meters you can buy the cheapest HDMI 1.3 or 1.4 cable you can find. Beyond that read the reviews on Amazon to find decent cables for a good price. Setting it up will take approximately 2 minutes.