You may need to install/reinstall DirectX 9.0c (June 2010).
https://www.microsoft.com/en-gb/download/details.aspx?id=8109
Hope this helps.
Yep, tried that too. Still nothing.Have you tried Restarting the PC. Not Shut Down. Restart. Win10 has "Fast Startup"/"Fast Boot" that caches info to the HDD when you use Shut Down meaning the old "turn it off and turn it back on again" doesn't work. Restart doesn't cache info meaning after a Restart is the new "turn it off and turn it back on again".
Okay it looks like I've got it up and running again. I followed this tutorial https://www.flightsim.com/forums/topic/42358-combat-flight-simulator-not-working-on-windows-10/
I downloaded dgvoodoo2 and put the file named "D3D8.dll" in the cfs3 folder. So far so good!