When playing most dvds the

When playing most dvds the picture will freeze for 2 or 3
seconds and ship 2 or 3 seconds and then continue. This
occurs on over 1/2 the dvds I play. Also on 2 out of 5, the
dvd will not load. The the loading bar indicater on the
bottom of the screen will load about half and then a
message will appear on the screen to eject the dvd. The
same dvd will play on other dvd players I have. I clean
the dvd player monthly. Can you help with this problem.
Thanks---Jim Hamby