Windows Media Player ... I am having a problem with my wmp. It was working fine, but for some reason I can't..

Play any movies on it. All I see is the equalizer bars and the visualizations waves. I can hear the sound, but no picture. These are movies I have played using it before. None of my media seems to work. InterVideo as well as Quick Time. I updated and that didn't work so I uninstalled and reinstalled with the help of a Tech. Needless to say that didn't work. I am at a loss. If anyone can help me PLEASE do. I will be very greatfull.