Thank you for the update caine0316.

One thing stuck out to me from your earlier post: "...it will work if I have my task manager open while running the game in windowed mode." What exactly do you mean by this? Does it work as it did before if you have the task manager open?

There are a few other things you can still try.

Switch to Directx 9 mode (if already in this mode, switch to 11).
Make sure that your anti-virus has the proper exception for Final Fantasy XIV.
Check the Program Settings in the Nvidia Control Panel and see if any settings are set to override the games settings.

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