Removal of other programs by Norton

Today I was running Norton Antivirus Quickscan.  During the process my program Regservo disappeared from my computer.  This naturally never happened before.  Does anyone know why this would have happened.  I was doing nothing at the time - Regservo simply was removed from my computer.  I run Quickscan frequently and this never happened before.  I paid for Regservo and I am more than a little annoyed at this event.  HELP !!!!