Car wont crank. Dash lights and fuel pump turn on.

My 1998 Nissan 200sx wouldn't turn over. I bridged the gap on the solenoid with a screw driver and the starter motor engaged but didn't engage the engine itself. I figured i had a faulty starter. I replaced the starter and the solenoid together because it seemed like a good idea. I installed the new assembly and still the car wont crank.

Any idea of what it might be?

In the last year I also replaced the alternator and the distributor.