I'm submitting this, even though I know the answer, just because it was driving me batty, and maybe I'll save someone else a headache. I installed SMPlayer on Windows XP, and found that any video I played would auto repeat (or loop, if that's the proper terminology). I searched all thru the interface for a loop/repeat button. It's *really* not obvious. I finally found it in Options|Playlist. That window has an arrow icon, which was on. Clicking it solved my problem.
Why on earth does this player come pre-configured to loop?