I was watching a tv series on DVD. I have had the DVDS years and they have always worked, but at around the 40 minute mark on every episode on 3 separate dvds they start glitching, freezing and skipping. It is odd it is happening at the same time mark and also I put another DVD in and watched it from beginning to end and it was fine...then when I put the other dvd back in it glitched and skipped again at 40 minutes. The DVDs are scratch and mark free...anyone know what could be happening?