This problem cannot have anything to do with GSX, especially if it happened after uninstalling, but it couldn't possibly be caused by installing GSX either.
The GSX installer and of course the uninstaller, will not affect any of the P3D .dll or other executables. It's not clear from your message what you did when uninstalling:
- If you replied NO to the question "Do you want to remove the Addon Manager" and "Do you want to remove the Couatl scripting engine" that are made at the end, it means our two modules are still started by the sim, but are not doing much, since there's no GSX anymore
- If you replied YES to the questions, it means the modules are not there anymore, so it's impossible the crash could be caused by any of our software, since it's just not there.
So, you might try answering YES to those questions, which would cause a complete removal. If you are STILL getting the crash, then would have final proof the problem didn't had anything to do with any of our products, and the fact you noticed it after uninstalling it was just coincidental.
If, instead, the crash doesn't happen anymore when uninstalling by replying YES to both the above questions, then it's possible (which might also explain why GSX didn't work) you have used the P3D Migration Tool ? Using it with our products that do recognize P3D natively and MUST recognize it from FSX, WILL surely cause crashes, because we'll be tricked into thinking your are running FSX (but you are not), so any direct access in FSX memory locations under P3D will surely cause crashes. The P3D Migration Tool should be disabled when running any of our products, especially the Legacy mode.