You don't say which sim you use. If you use P3D 4.1, some users reported a problem with black textures, and not only on GSX, but on some airplanes too, so it might be an issue related to video drivers or shaders.
But even if you don't have P3D 4.1, if you have the GSX vehicles visible, but with no textures, the problem doesn't have anything to do with GSX. If you had this problem before, it's entirely normal that a new GSX installer won't fix this, since the problem was never GSX to begin with.
With FSX, the most common cause of problem is applying undocumented video tweaks that might not work with your specific card, so you should try all of these:
Reset your video driver to default
- If that doesn't work, try to delete your FSX.CFG, so a new one will be created with all default settings. Apply only the HIGHMEMFIX = 1 tweak and nothing else, if you use FSX.
- After you reset the FSX.CFG, you must reinstall GSX.
- If that doesn't work, be sure you are not running the sim or any of the addons that starts with it in Compatibility mode.