1997 Dodge Grand Caravan Question: having problems with windshield wipers not working

We just got out van, and when I used the wipers to wash off the window with some fluid, they made a noise so I stopped. Then my husband had to use them because it was raining on his way to work, and they quit moving. You can hear the noise from the motor, it's a rather loud noise but the windshield wipers themselves will not move. Any ideas on what could be wrong? Or how to fix it?