could it be.............one of my favorite movies??? The Final Countdown???
The very movie that made me have doubts that the future really was changed at the end of Terminator 2, because if they had prevented the war of the machines, John Conner would never have been born. (Lasky's "What if I went back in time and met my very own grandfather, and got into an argument and killed him? How could I ever be born?" speech.)
Props to you, Julix!