Is there an option to play in window mode?
I have Windows 7.
I go to C:\Users\Admin\Documents\Settlers7.
Open the Options file.
Change FullScreen = 1 to FullScreen = 0.
Save the file.
Did that work for you?
Sorry I forgot to mention I am running a iMac
I think you should still have the options file that you can edit. I just can't tell you where to find it.