Reset??

Is there a way to reset this system. My nephew gave it to my daughter and it started acting crazy and skipping around on the cds. I opened it up and sprayed with canned air, cleaned lens with alcohol and put back together. Then cd changer drawer won't open so I carefully take apart again while stopping every so often to try to open the drawer. Well, it had to be plugged in to do that. But when it was on and apart the screen showed a "protected" message and when I put it back together it won't come on at all. Is there some sort of combination of button pushing that will reser it?