Samsung 3650 dvd/vcr player loading problem

When trying to play a DVDthey generally won't start. Player says "loading" for long time thensays "this disc cannot be played---check the disc". Following thatplayer may display "play", then in a second, or two, displays "stop" onthe screen. Player may repeat all this several times, then it maysuddenly start to play the DVD. This happens with almost all DVD's. Ican put them in computer DVD playerand they work fine. If I keep trying to restart the player, eventually,after about 10 to 20 tries, it will play the DVD with no problem.