I have an AudioVox 7" portable DVD player, Model D 1718PL. The unitturns on, the screen lights up and displays the AudioVox logo. When iput a DVD into the unit it says that it is loading. The disc starts andruns a bit then stops and will say no disc. We've had this unit for only 10 month and it was playing well till now.Any idea what may be wrong with this unit?thank you