3D stopped working

I have an Inspiron with nvidia 3D VISION that came with nvidia 3D vision 2 glasses. I was able to watch one 3D movie on it a while back, but now it doesn't do 3D. The test under nvidia control panel also doesn't work. I charged up the glasses until the yellow light stopped flashing. I remember struggling for hours to get it to work the last time, but it eventually did. This time nothing I do works.