I have a dell comp that came with a dvd burner. It seems every movie I burn using decrypter and shrink always has playback issues. Every movie I have made plays fine until close to the end than the picture and sound starts breaking up. I have tried different dvd brands and upgraded my ram to 768mbs and that hasnt helped any. I always turn off the screen saver and all nonessential programs. What can be causing these problems?