Hi all my copy of sc3ku is running in a small letterbox and is making my game unplayable. I have changed to every display setting on the game to no avail. I have even changed my display settings and getting the exact same result

There's a program called DxWnd, it makes old DirecX games work in modern hardware. Just be sure to enable "Expert Mode" on the menu and you should be ready to go. I'm making a guide on it soon...