CD Player not working after being disconnected

Hello! First time on the list. Just bought a 2003 Suburban with a 6 disk CD changer in the dash. I had XM Radio installed, and the tech that installed it unplugged the radio from the harness and plugged it back in, and now the CD player portion of the radio does not work. All I get is a flashing disk image in the upper left hand corner of the display. Pressing "CD" does nothing, Pressing "Eject" says that there are no disks. (There are 5 disks loaded) Pressing "Load" does nothing. It was working great before this happened... Anybody have any ideas? My next step is take it ti the dealer, but I know there is probably something simple to do to restore function!

try unhooking the battery for a few hours, it will reset all the electronics. if that doesnt work, take it back to who did the install and make them fix it, they are liable for all work performed on the vehicle

-Rob

Thanks for the reply. That was my next step. I'll try it this weekend and post the results. I had the install done at Tweeter, and I know they are responsible, and they said that they would pay any charges I incurred at the dealer. But If I can avoid the hassle of taking it in, I will. Thanks again!
Toaster

your stereo is a teft lock model... if power is lost on it you have to place in it your 4 digit code that was programed into it at time of purchase... if it was not given to you you have to take it to dealership so they can reset it... it's susposed to prevent theft by not working until code is put in ... in event it was taken from vehicle and placed in another

I suspected as much.... I just don't seem to be able to find the time to get to a dealer. Thanks for the advice.
Toaster