Emerson ewc1302 13 in. tv/vcr combo problem (by 5 users)

I have one of these units, which up until yesterday worked fine.  My son played a VCR tape in it, worked fine.  Later, we tried to play the same tape, you can hear the audio from the movie, no picture, just a snowy screen.  Other tapes are now the same way....sound but no picture.  Is there something that needs reset, or what?  This is a 2002 model.  Thank you!