You said you don't think it reads CDs. Well, if you put a game in it and it spins up and stays spinning and sound comes out you'll know if it does or not. A CD game running the attract over and over again will leave you with the drive light on all the time and CD access every once and a while, regardless if you can hear anything from the TV.
A lot of TVs won't play audio if the video signal is out of range, so hook the audio outs into a stereo or computer or something so you can see if it makes sound.
If it does make sound, and if you are sure your cables are good (there are a huge amount of junk DIN style AV cables out there) and that your TV works and everything the first thing to check would be the AV socket on the system itself. It could be buggered out from people stepping on the cable, or it could have become disconnected from the board.