Answer: How to make Storyline completely FULL SCREEN and BORDERLESS!

I found a solution to this long-lasting mystery!!!! 

Making your .exe output FULL SCREEN with no borders:

After turning off all menu items in the PLAYER settings, go to the COLORS & EFFECTS settings and choose "Show advanced color editing". This does not look like a link, but it is.

Select all frames/borders and make them 100% transparent!

NOW,  go into the loader.ini file in the root of your published output folder.

Change WindowStyle to zero:  WindowStyle=0 
(changed from 2 as the default)

This will get rid of the annoying border at top of screen! 

You are now 100%, entirely full screen with NO BORDERS AT ALL!