What I have to do?

I just downloaded the free Windows 10! Stupidly, I neglected to check whether it likes FSX before downloading. It turns out it isn't compatible with the version of DirectX FSX uses. There are a lot of shortcomings in W10 and so I recovered back to W7. All seemed well-ish until I installed a new aircraft in FSX. It runs the sim ok but when I come out of it a 'Fatal Error' warning pop up and FSX closes and then restarts returning to the default flight (the micro-light) rather than the chosen flight and at Friday Harbour rather than the chosen airport. Running all previously added aircraft produces no 'Fatal Error'.
I have reinstalled FSX and SP1 and 2 but with no effect. Is it necessary to delete all the downloaded aircraft rather than leaving them intact during uninstall? Putting them back takes so long!!
https://www.microsoft.com/Products/Game ... Pack1.aspx
I have reinstalled FSX and SP1 and 2 but with no effect. Is it necessary to delete all the downloaded aircraft rather than leaving them intact during uninstall? Putting them back takes so long!!
https://www.microsoft.com/Products/Game ... Pack1.aspx