I already did a complete reinstall of P3D and not only the client install.
Have you removed ALL your addons before uninstalling the sim ?
Have you removed ALLO those folders from the previous installation ?
%APPDATA%\Lockheed Martin\Prepar3d v4
%PROGRAMDATA%\Lockheed Martin\Prepar3d v4
%LOCALAPPDATA%\Lockheed Martin\Prepar3d v4
Documents\Prepar3d v4 Addons
Documents\Prepar3d v4 Files
Have you removed any remaining P3D4 main installation folder ?
Have you reinstalled P3D4 and GSX immediately after, so you can be sure the problem is not caused by other addons ?
If you haven't done *all* of that, you cannot be sure yours is a really "clean" installation.