2002 Chevy Cavalier Car wont do anything

My daughter was driving her cavalier on the freeway last night and it just stopped. Nothing worked but the brakes. According to her she still has lights on the dash but nothing else. They were able to get it off to the side of the road but had to be towed from there. Any ideas as to what may have caused this? She is having it towed to a repair shop today but it would be nice if we had a heads up as to what the problem is. Help!