Engine does not crank after a loud noise and shutting off?

Oh no " its probably best to have it towed into a shop and get it up in the air and have a Mechanic get a good look at it. Good luck

Loud noise followed by no start is not a good thing. I would try turning it over by hand and look around on the engine for any damage, like a hole in the block. Did it lose the oil or any coolant? The description sounds like engine failure. If you try to rotate the engine by hand and it doesn't move, that would almost confirm it. You might be able to reach in there with a camera and get images easier than fighting to see it directly.

Okay, if the engine turns and the starter spins but doesn't engage you will need to get under it and see why. A loud bang could be pretty much anything, from a bad converter that shoved the ring gear out or the ring gear itself may have failed. Could even be something like the crankshaft broke and only the back of it is moving. But it's going to need a visual inspection.