I own a Polaroid personal

Question

I own a Polaroid personal DVD player model pdm-0711. I love it. It hasn't been used a whole lot and I keep it carefully put away when not in use. I recently took it out to use it and found that it would play a music cd and will also play a picture cd with all photos on it, but for some reason it will not read a dvd. Any dvd. Dvd's I've watched on it before... what could be wrong? Is there a setting somewhere I missed? or is it fried? Please help!