settings for a 1024x768 monitor that Trinity insists on recognising as 800x600.

The main problem at the moment is that I cannot set up KMail because I can't get at the bottom of the window. :-( It is the first time that I have used dvi-d and the Iiyama Prolite E431S has heretofore been recognised well in VGA. I obviously need an x-org file, but am not sure how to achieve this at this stage. TDE 3.5.13.2 on Squeeze, just finished installing and am trying to set it up. NVIDIA GTX 650Ti 1GB Graphics Card. Nouveau is installed. As a pro-tem measure, can anyone remind me how to move a window above the top of the monitor so that I can get at the bottom and click "apply"? :-( Thanks, Lisi