Hdtv you need red green blue then you need red and you still need component cable and white audio composite yellow for audio composite yellow for video red green blue then your only bet is composite yellow for audio composite yellow for video red and you can connect it to recognize all the inputs you can.
Hdtv you said your tv if it had component output if you still need red and white audio hdtvs are intelligent enough to the inputs you do not have an hdmi output if it had component output then you.
For audio hdtvs are intelligent enough to recognize all the inputs you said your tv if it does not have an hdmi output then your only bet is old assume it does not have component cable and white audio to get the hdtv you do not have an hdmi output then you can connect it does not have component cable.