cd in 2004 chevy malibu doesnt work?

I disconnected the battery to shut my engine light off and ever since my cd changer says error. It make noise like it wants to work but doesn't, it's like the car is not recognizing it. The errors "no disc" show up and nothing will eject or play. I tried re disconnecting the battery for 20-minutes and that didn't work either, I also tried taking the fuse out and replacing it. Please help!!! Is there some reset button.

beth
March 2010