Why wont my car start?

I just bought a 1996 mitsubishi eclipse. When I got the car it wouldnt start unless it was jumped off. I took off the alternator and the battery and got them both tested. The alternator was fine but the battery was bad, I put on a brand new battery and put the old alternator on and it wont start period. Bought new starter, spark plugs, spark plug wires, and coil pack and now it just turns over without actually starting.