The dvd player displays "no disc" sometimes.

I have a GE DGE100N dvd/cd player. Sometimes it displays "no disc" and other times it functions fine...with the same dvds in quesiton. These are store-bought dvds, not burned from computer, etc. I insure that the dvds are clean and free from scratches. It's as if the player has a mind of its own. I unplugged it for a couple of minutes, reapplied power, same thing. I unplugged it and removed it from entertainment center, replugged it, and now it IS reading the dvds...all of them. Have u heard of any problems similar to this?