Don't use ff7w uninstall / remove it
, use Aali's driver instead: copy the ff7_opengl.cfg to the desktop and open it in notepad (it's part of Aali's driver), scroll down to resolution and set the resolution to a square resolution, then where it says full screen= yes, change yes to no and save the cfg and put in back into your ff7 directory. Make sure you run ff7.exe as an admin and your problems should be solved.
Also remember that once Aali's driver is running don't open your ff7config file as it disables the driver and will use the original driver again