Broken Game

Hello, My finished game that I started making in stencyl 2 no longer works. I do have stencyl 3 installed on my computer, but i've only opened my game with stencyl 2. The only thing I get when I test the game in stencyl 2 is a black screen... this troubles me.  any good news or advice?

Can you be more specific and provide a little bit more info.
What operating system do you use?
screenshot/logs are always welcome for debugging.