Oh - I forgot the
commonest reason for the skewed desktop, naturally!

. Insufficient tea this early in the AM..
If an end user has not followed the installation instructions and has not
disabled auto-hide for his Windows task bar then that happens as the graphics engine was written before Windows had that feature (I think) and so gets the wrong screen size reported to it at initialisation.
So make sure your Windows task bar is
not set to auto hide, and it is in the default position and size at the bottom of the screen.
cheers
Andy