35,000 miles on the car and for some reason our car won't start.

What is your question?

the car was working fine,then all of the sudden,it would not start, this is the we took the battery back to auto zone they replaced the battery, put the battery in the car, at first it seemed as if it was going to start but it didn't so we took the battery back the guy said that the battery went down 40% and that he couldn't do anything with the replacement battery so he charged it and gave it back to me.so thats it.it never started tried jumping it , no luck won't start.the car only has like 35,000 miles on it.