2002 Chevy Impala

I was driving My 2002 chevy impala and cut it off
to wait in line to pick my daughter up from school
and it would not crank, it turns but will not actually
start, I hAd a mechanic come over and he thought
it was the fuel pump so we replaced it and its still
doing the same thing. He says he thinks it could be
something electrical or in the computer and that it
would cost just as much as the car is worth  has
anyone else had this problem? And what did you
do?