Engine not turning

1999 Ford Contour, 23,000 miles, Not sure of engine size. My wife was backing out of the yard when it sounded like she was dragging a chain down a gravel road for a couple of second. At that point the engine died. I was able to take the car out of reverse and put in in nuteral to push the car back into the yard. When we turn the key, all of the belts turn, park plugs fire, and everything in the car turns on, but the engine will not fire. I am wanting to fix this problem myself, but I do not know what the problem is to fix. Any help anyone?