I can't believe it was just one update for Windows 10 that broke your FSX. I mean, there are a lot of FSX-users running Windows 10 too, most likely up-to-date (as there is no other option :rolleyes:).
Can you pinpoint it down to one specific update when FSX decided to go full-bug-mode? Maybe one can find a solution to fix your problem.
I had the boxed version of FSX (FSX Deluxe + Acceleration and all of its patches, if there were any) and now FSX Steam Edition running on my new PC (bought it in December 2015), which had Windows 10 pre-installed as its OS. So far, with every big or tiny update FSX still runs like a charm, along with all meshes, sceneries, planes etc..
Only thing I can tell is that FS2002/FS2004 had some issues on my machine, but there were existing fixes that one could find on the internet (such as compatibility mode).