Campaign-Mode crashes to Desktop

Hi, I hope someone could help me with my Problem.
I recently bought CFS2 an installed it. Everything is working fine except flying a campaign.
The Trainingflights, Single Missions - no Problem. Then I choose the Campaign, create a Pilot and click on "Go Flying" it returns me immediately to Desktop.
Tried almost everything, defragment the Harddrive, new Installation, No-CD Patch, reduce Hardware Sound Acceleration, reduce Graphics Detail, nothing worked...
It's a fresh Installation without any Add-Ons, my System:
WinXP
German CFS2
AMD Athlon 900
512 MB SDRAM
GF2 Ti (Gainward)
Any kind of Help is welcome. :)
I recently bought CFS2 an installed it. Everything is working fine except flying a campaign.

The Trainingflights, Single Missions - no Problem. Then I choose the Campaign, create a Pilot and click on "Go Flying" it returns me immediately to Desktop.
Tried almost everything, defragment the Harddrive, new Installation, No-CD Patch, reduce Hardware Sound Acceleration, reduce Graphics Detail, nothing worked...
It's a fresh Installation without any Add-Ons, my System:
WinXP
German CFS2
AMD Athlon 900
512 MB SDRAM
GF2 Ti (Gainward)
Any kind of Help is welcome. :)