electrical problems on 1990 Chevrolet Cavalier

car will not start and i have replaced crank sensor, fuel pump, filter, different computer, checked relays, replaced fuses

2 answers
Do you have gas in it? Not to insult you but Don't trust the gauge it may be wrong. I had the same problem with mine not starting and found out it was out of gas because the fuel sending unit was bad telling me I still had a quarter tank left in it. Also could be a bad pump can you hear it kick on when you turn the key on?
you might have an open in starting system wireing check starter's ground or you could even have a seazed up engine UTI'S FINEST NOAH