RCA RC5220P DVD Player
You have to unplug it between viewings!
Am on my third one of this model...each one with the same problem.  After a few viewings, it began to get choosy about which DVDs it would read.  Sometimes it would not even acknowledge that a DVD had been inserted!  I finally figured out how to fix it, since RCA could not.  When it does this, you have to unplug the machine from the outlet for about a half hour.  Apparently this resets something and allows it to read again. Now, until I can replace it with a better machine, I unplug it each time I turn it off.  So far, this works.  It's a shame...I have always liked RCA until this machine.  It performs GREAT when it works, but I will think twice before I buy an RCA product again.