how to fix my ford fiesta?

i was having trouble trying to reverse my car off the drive in the snow after reving it a few times going back and forward it totally just shut down , its always started 1st time with the battery i dont know whether ive just reved it to much and the engine has gone , ive been told all different things also been told it could be the cutt off switch that needs to just be switched on but i dont know where to find this could any1 please help me im out of my mind