CD Player Problems

I have an AM/FM Stereo, CD/DVD, Navigation system that I've had problems with from the beginning. First I lost all audio...no radio, no alarms, no blinker noises...nada. The dealer replaced the radio and amplifier.
Then I bought 2 new CD's and the first one hung-up after 30 seconds. I figured I had a bad CD so I went right back in to the store and got another one...same thing. I played this same CD at home and in my wife's Volvo and my buddy's Chevy Avalanch...no problem. It happened on another one also so back to the dealer it went. They agreed there was a problem and another radio was installed today. SAME problems.
Anyideas out there???
Thanks.

Dam, thats a bad gremlin. I hate electronic gremlins. But I am sure they will find the source.

Is your problem with the radio/cd player only, or are other systems failing? Are you loosing warning chime etc? Please list all system failures. Also note: there are multiple electronic control modules (ecm) on board. Chassis module, bulkhead module, abs, engine on & on. When you loose operation of more than one power consumer / circuit. I would start with the controller in charge of those consumers. Gents, the days of just replacing a fuse or relay are OVER.

Not 100% sure, but isn't there some sort of speaker control switch behind the centre console? In fact I KNOW it's there...my kids fiddle with it all the time). I just don't know what it's for.