Hi Leslie, thanks for your quick response!
During the weekend I did a complete un-install of Storyline. I shut down my PC and restarted - then I installed the latest version of Storyline.
No change to the problems encountered with previewing the Storyline file!
I have followed the additional steps including verifying that the Microsoft Net Framework 3.5.1 is enabled, completely uninstalled the Flash Player using the uninstall program, shut down, & reinstalled the latest Flash Player.
I am still at the same place where I was previously - Storyline works fine for a while - I've just been putting together a completely new course - and previewing after every edit - you get a bit paranoid after a while! So I've reached the 7th slide and added my content and now I can't preview again!
The weird thing is that if I copy all my Storyline slides from the affected file to the clipboard and paste them into a new Storyline file it works fine - for a while. After editing for a while it always gets to the point where the file cannot be previewed.
All my resources are in the same folder as the Storyline working file.
It's a shame that I have to do all this messing around just to publish a course - Storyline was working perfectly before!
I've submitted a case on this problem.
Thanks & Regards