Help removing importing sound file

Hello there

I'm pulling my hair out trying to figure out why storyline won't delete my audio file.  I added a "button down" audio sound effect to my whole project, and when playing back I can hear the sound effect as soon as the playback starts.  So I thought it had something to do with the positioning of it on the timeline. 

Fast forward  >>>  I deleted the audio files from each slide and layer.  But I can still hear the damn click!  I loved hearing it before - but not anymore!

Help please

Shiraz from Sydney