For a while now, when I load up a flight, while its loading I alt+tab to browse the internet. And when I come back to FS9 its all done loading, but Im not on the run way, Im either in the air(if its a small a/c) or on the ground moving, or have crashed already. Basically, it starts my flight without me telling it too.
I suspect your AI is pushing you off the runway. It sounds wierd, but try turning your AI off and then see if the problem goes away.
I'm guessing here, so I could be 100% wrong.