The component video (blue/green/red) only carry video information no sound. So you have a couple of options, if your TV has another audio in set of is stereo (red/white) and your DVD has a set of stereo out RCA jacks then just need to add them. If your DVD and TV have either optical or coax digital (orange for coax, little black box with a red light shining out for optical) then you can get a digital optical or coax cable and get audio.
There are some 1/2 way measure I only found recently when someone asked about going from digital out to stereo in and I found a number of converters out there that will do this but they are not cheap.
Your best bet is to get a Home Theater Receiver that has the right mix of analog and digital inputs, they come from pretty low end, under 200 bucks to mid-range around 300-700 bucks to higher end, over 700 bucks... (Cost are my measure, your threshold may vary).
I got a middle ground Sony that had a great mix of HDMI, Component (red/greed/blue), S-Video, and composite (yellow), stereo (red/white or red/black, coax digital audio (orange) and optical.
The sony allowed assignment of just about any vidieo input to any audio input set, and then pumps them out to the TV over HDMI, it even has other outputs but there are limitations on them depending on your source.
No matter what, if you don't have additional inputs you will need some kind of "box", I suggest a HT, but there are the other methods also.
It is amazing how far backwards we have gone with all of this new stuff, in the "old days" a mere few years ago the only real questions for the typical consumer was how big a TV, quality of the screen, and getting one of three kinds of patch cords, S-Video+A/V, Composite (red/white/yellow), or RF, now there is component, HDMI, plus all of the prior choices and they all make a material difference on what you get and can do with them.
No wonder Geek Squad and all of thee other installers is making a fortune on nothing more than hooking up a darn TV set, DVD, and Cable box...
Best best, make friends with a good A/V techie and offer him/her a nice lunch or a brewski to come over and get your stuff going
I have lost count on the number of free meals I have scored with this new stuff!
I just bought a Samsung 32" HDTV. I was unable to use the existing white/yellow/red cables so I bought some of the blue/green/red cables.
Actually, I bought two sets of them and also two sets of the blue/green/red/white/red cables.
I replaced my cable box with HD and used one set of the blue/green/red/white/red cables from the cable box to the TV. NOw I see the TV beautifully with the surround sound.
I am not able to play a DVD however. I replaced the white/yellow/red cables from the DVD to TV with blue/green/red.
I get picture but no sound.
Can anyone help me?

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