Hi Lisa:
If it won't shut off then the ignition is on all the time.
If the start switch won't spin the starter, then the switch is not working.
Something happened to cause this problem.
Who did what to the wires? or
It did it all by itself in which case the switch needs to be replaced.
I would use a continuity meter to check the function of the switch and make sure the wires are correctly connected.
Hope this helps.