Brggs and straton mower won't even turn over?

Last summer I replaced my battery. Yesterday I got a "rent a husband" to look at it and the spark plug is fine and so's the battery. When I first bought it the silver rod under the seat to put into neutral unless it was in a proper position wouldn't let me start it...I unhooked the connection under the button that would push down when you sit on it (it's like something you would plug in a wall) and there are three holes in it, two have wires plugged into it and one dangles and doesn't appear to have a place to go...it's on 1 1/2 inch so it can't go to far, any ideas? My husband is disabled...my yard is big....my arms are killing me.