I have spent a fruitless afternoon with all sorts of gremlins and weird happenings with FSX and the Captain Sim. All began when I used the Capt Sim cold n dark and then relocated it to Avalon in Australia, then I changed the fuel and pax loads. From there on in nothing I would do would get the no 1 engine to start and so think I did not understand the systems from there on in when I tried to load another flight windows decided they were all the same and no matter what aircraft I would load it would not start the engines. Even the Trike would not start.

Solution you guessed it, shut it all down, reboot and start all over again.
Hrummpph #$%@!! :-/

Although I only have those kind of problems when switching from one advance aircraft to another, I have found that if I load the default C172, then the next choice of advanced aircraft works fine. But NOT every time. If I do this about 4 or 5 times, FSX will then crash and I need to restart it. I don't need to reboot my computer to get FSx back up and running properly.

Mark