My 1989 Chevrolet truck will not start. When I turn the key the radio will not even turn on. The motor will not even try and turn over.

I have a 1989 Chevrolet 1500 pick up truck. I was told to replace the ignition module.  
After I replaced that part the truck still would not start. When you turn the key it is very
rough or hard to turn. Sometimes it will not even turn.  I am confused because the
headlights and tail lights work but the radio doesn't work and the windshield wipers do
not work and the truck still does not start. What do I need to do?