Crank sensor replaced, why is the car still not starting when you first turn the key?

Told crank sensor needed to replaced.  It was done, plus new battery.  This problem began around May 22, 2014.  No service engine light warning.  Try to start the car, nothing happens, lights still working, clicking sound when you turn the key.  After replacing sensor, car still really not starting when you first turn the key.  Have to turn the key over twice before the car will start.  Is the computer in the car going bad?  Something not clicking with the sensor for the car to start up quickly. No service engine light warning, car runs fine once it is running.