Changing the way slides advance

I'm assuming from your reference to On Mouse Click and Automatic that this is a project which you have created with PPT and Captivate?

If so, when you imported the PPT slides you must have selected the On Mouse Click option.  This results in each slide having a click box object that pauses the slide and listens for a mouse click event to allow Continued play.  Just locate this click box on each slide and delete it. 

And before you ask...no, there's no way to do this across all slides in one go.  You need to manually remove the click box on each slide.

If this would be too time consuming, your quicker solution might just be to reimport the original slides and make sure you select the Automatic advance instead.