Well, if the temps are fine, obviously it isn't a heating issue, and with the additional information, I have a suggestion for you. In your documents / my games folder should be a folder for Final Fantasy. Create a folder on your desktop, and drag everything in your documents/games/final fantasy folder into the folder on your desktop. Return only the Users folder back to the FF folder, and launch the game. If you have -not- customized anything (no key bindings, haven't moved any widgets, changed chat colors etc.) then don't restore the users folder either.

Seems to that those steps fixes a lot of local problems in FF, so give it a shot, see what happens.