Having a problem running flights on my msfs 2004. Keeps crashing back to windows

I am running windows XP. The game just crashes back to windows any time I try to run The Wright Brothers flight, and most of the flights after that. I can create a flight and run that. Most of the scenic flights will run. When I first bought this program about 4 years ago I had only 1/2 gig ram and I specifically remember being able to run the flights that crash back to windows now. I have reimaged my computer since then and now have 1gig of ram. Can someone tell me what could be the problem?

P.S. I also installed the patch fs 9.1 and that didn’t fix the problem either.

                Thanks, Jo