Hi Mr Pete Dowson,      
 I Have window 7 for my FSX  which is my Desktop pc and i Have window 7 on my other pc were i run my FS Commander and  WIDEFS so it  connect to my FSX in my Desktop .  when i shut down FSX first  I got what you see in the video 
 Error "Runtime Error R6025 Pure Virtual Function Call .   so i ran my REG CURE Registry cleaner i also ran a defragment and malwarebytes also fsx registry to help fix this problem so i couldn't fix the problem  so i  reformat both pc and install  everything back and that  fix  everything ..  fine  but  !   I  came to understand what cause this problem was my WIDEFS ?   Just  Cause i forgot to shut down my WIDEFS first and now i have it again  so i dont want to reformat both pc to fix this  and widefs is causing this problem by not shutting it down first do you have a fix for this the problem is not my software is widefs  the is making this happen also i have all the new Version
  
 so please click on link and look at my video