Loud snap and car won't go in reverse.

What is your question?

Yesterday on my way back from the store a heard a loud snap and the car started didn't want to accelerate. I got the car off the road and cut it off. It will still start and drives but it isn't driving right. I only drove it a few minutes to put it into someones driveway in the neighborhood. It won't go into reverse at all. What might be the problem? Thank you for your help.