Adrian, I have the same problem. FSX starts with my default flight and that is pretty stable. However if I decide to go to any different airport, within 1 minute of starting at the new airport, FSX stops and message box displays stating that FSX has encountered a problem and must be closed with an OK button. No other explanation of why. I changed FSX.exe to run in Win7 Compatibility mode as well as run as adminitstrator. That actually helped until the last cummulative update from Microsoft on 9/9 after which the problem began again. Very frustrated....Wish I knew where the incompatibility lies......
Buena suerte Adrian.....
Gil Diaz