Extra Frames in Sliding Menu

I put all the content together & somehow during that I extended the movie to 2 frames & now I cant get it to go back to one frame. Basically all the movie does is flash from one frame to the next. Kinda like a strobe light. ARGHHH!

What can I do? How do I make the movie go back to just one frame? Where I can’t move the center frame beyond frame one?

Help please!
Thanks in advance!