1994 Jeep Cherokee car wont start

A couple weeks ago my altinator went bad. Replaced it. Then the car wouldn't start thought it was the battery b/c the car needed a jump to start. Then a day later I drove the car for 1 hour straight stopped shut the car off tried to start it and it wouldn't. Tried getting a jump (with my new battery by the way). Turned the ignition no noise. Took a screw driver to the starter and it turned on right away. Next day tried to start, wouldn't, not even with a screwdriver to the starter. Tried a new starter, wouldn't turn over. Put my old starter back on used the the screwdriver method it started. Is it my ignition switch bad or what? If so how do I definetly confirm thats the problem? If thats the problem how do I replace it and is it expensive? Are any special tools needed? What is the nuetral safety switch, and where is it?