Sometimes if you were for instance running at like 1024x768 and then switched to 640x480 at some point a window like explorer or something may be larger then the 640x480 from when the rez was bigger. In this case, you may be able to just hit the maximize button cuz this will make it fit exactly to the screen size. On the other hand... there ae some screens that are a fixed size like the windows display properties that you cant change..... You may be able to sorta grab the window and try to move it up some to reach the ok button. I have this issue too sometimes because 640x480 aint a lot of screen real estate.