If you start FSX, put it in windowed mode, and exit out of it, then it will continue to boot into windowed mode until such a time as you put it back into full screen mode and exit that way. it basically saves your last window state on exit.

I am having the same problem, with the computer freezing when trying to access any of the drop down menus, but it has nothing to do with Acceleration or SP2. I have the works installed and FSX was running better than ever..a constant 23FPS with all sliders (except traffic) set in the middle or higher. I then upgraded the processor from a Athlon 64 3500 to a Athlon 4200 X2...now it crashes when I try to use a drop down menu. I changed nothing but the processor!! Any ideas?ThanksSean