Happened to me 1 time with my old Mercury. The key cylinder for the ignition switch is spring loaded for the start position. I let it go & it sprung back just a little too far. I drove about 8 miles on my way to work, then the car just shut off. I came to a stop, re-started & off I went.
Turned out to be a recall item that I had taken care of the next week.
If you have a PATS system, it may be more involved than that, but its a place to start.
Did your car start up again later, or is it still dead?
