playing a flash movie exported to SWF
Are you exporting a SWF or FLA—you can't open a SWF in Flash. If you are exporting an FLA, the Movie Clip assets have no code on their timelines, so when you test the movie nothing stops the timelines from looping. At a minimum you would need a stop() actionscript code on the first frame of the main timeline.
Thank you very much for a most useful help – only nothing happened when I placed the stop() as you suggested – when I placed it at the end frame, hooray – the movie stopped