Water in gas tank causing problems?

I have a 1996 Cavalier. It ran out of gas, so my brillant daughter grabbed the small gas can from the back of the house, which felt half full to her (1 gallon) and smelled like gas, so she put it in the tank to get her to the nearest gas station. It worked, but the problem is that I told her that can sat since last summer outdoors and probably had water in it. She put about a half tank of gas in the car, and when she went to pull out of the gas station, it sputtered and then shut off. It won't turn over now. We put a bottle of dry gas or whatever in it, but it still won't turn over.

Any suggestions??