Want to buy a blue ray player and hook it up to a all in one dvd home theater system. Will get the blue ray video with surround sound by doing this? Or can I take the dvd player off and hook the speakers into the blue ray?

i can't get the sound to come through when watching tv but i can get the DVD player to work. I am not sure what i am doing wrong, or if i am missing a cable or something. I have a VIZIO HDTV if that helps any. I have an HDMI cable going from the cable box to the tv, and then i used the RCA cables from the tv to the home theater system but that i not working just the DVD player.