Thank you for the update Luxerion.

As a quick test, try running the game in DirectX 9 mode. This can be selected from the 'Config' menu on the launcher.

It could still be a corrupted file. I'd suggest doing a reinstallation of the game if you can. You can redownload the game here: https://www.finalfantasyxiv.com/playersdownload/na/

If this does not work, try some of the following:

-Update/reinstall Graphics card drivers
-Disable all programs/overlays running in the background
-Set compatibility mode to Windows 7 (right click on the exe file and select ‘Properties.’ Then select the ‘Compatibility’ tab and choose Windows 7)
-Make sure that any anti-virus software they have has the appropriate exceptions

We hope we can be of assistance in helping you enjoy the exciting world of Final Fantasy XIV!