After selecting which video adapter I have, an option is available to 'Test 
X configuration' -- when clicked, the selected X server is started, and a 
dialog box is displayed -- off the screen to the lower right corner.  While 
it can be accessed by scrolling to the lower right, it _should_ be centered 
-- ie, the virtual resolution should be the same as the physical 
resolution.  This is before the resolution and color depth selection 
dialog, which also has a 'Test X configuration' button.