So here's my story (yesterday).
2750 miles on a 1.5 month old Focus. I get into the car and it won't crank. Battery seemed ok. I manually pressed the clutch switch, no difference. I noticed instead of the mileage, the dash shows a number of dashes (-). I get out and wait a minute, just in case the anti theft has mixed up, no difference.
I call ford roadside assistance and they sent someone to tow me to the nearest dealership, which is already closed at 8pm. Not the best thought I must say

It would have been nice if they had a mechanic on call to help diagnose simple problems for people willing to try, but they didn't have any.
While waiting, I checked the manual to find out what fuses are related to the PATS / ECU / starter /.... I checked the fuses, but they were all fine. Then I looked at the related relays, the first one I swapped was the ECU relay and bingo! Now I have no AC though
I called Ford roadside assistance back to dismiss the tow truck.
It's a shame people get stuck for such a simple problem. I wonder if all the Ford relays are low quality, or was I just too unlucky.
I went to a dealership today (I'm in NJ, 1900 miles away from home (TX)) and told the service advisor my story. They wanted the car to stay for today, which was impossible for me without a rental. So they scheduled it for tomorrow morning. I wonder if they are going to say you modified the relays so it's out of warrantee?! :|
Anyway, I guess in this FAQ, you should mention checking related fuses and relays
Best,
Ahmad