1990 Celica...tired to fix it and don't know what to do now

i was just driving last week and my car shut down, and was wondering what had happened, i had to get it towed home and the next couple of days i had been thinking its the gas filter or the gas pump. well i checked out the gas pump and that was fine and i replaced the gas filter but my car still won't start. i mean when you turn it on the radio, lights, headlights, etc, all work and when you try to start it it just spins, can someone plz help me????