OK, I recently noticed that I was unable to use Windows Update at all. I would get an error message each time it went to the WU webpage.
After emailing back and forth with MS for a week, I was able to update. However, .Net Framework update would not install. It kept giving an error. So MS finally gave me a phone number to call and speak with a .NET tech. We were on the phone for several hours. It turned out that one service had not started (cannot recall which one now. We started and stopped so many!) So now I have all the updates completed and it was a lot!! It took several hours and multiple restarts to get them all installed.
This seems to have fixed the issue of crashing after long haul flights too. We've flown now several long flights, including the longest real-time flight yet from Amsterdam to Tokyo. Both are add-on airports. We used the new REX for weather (amazing!), PMDG 747 and FS2Crew.
No issues! Knock on wood!