Will not play the entire DVD

your dvd reading head is out of sync open the lid hold the button that is pressed when the lid is close now with your finger move the head till the screen say's no disk that should be right to the center place a disk in and hold the button with your finger and notice a red light under the disk rotating pressing the next of fast forward button watch the light go to the outside of the disk . it should go right to the end without making a noise and read the entire disk if not keep moving the head till it does . your problem should be fixed there is no other reason to read only a part of the disk other then the disk it self is dirty.