this morning suddenly the preview of SL stopped working. After attempting to reinstall the program, I later discovered that the problem was created by Adobe Flash. So I found and followed the directions posted in "Preview Isn't Working in Articulate Software with Flash Player 220.127.116.117 Installed".
Preview now works! I want to know how to behave in the future! I will have problems with other versions of Adobe Flash? What should I do with the next updates? Thank you