How do I play Call of Duty: United Offensive (Single Player) in Windowed Mode on a Mac (3.2 GHz Intel Core i3, 4GB 1333 MHx DDR3, bought March 2011). The game locks-up when following the Shermans out of Foy. Aspyr Tech Support suggested running in Windowed Mode, but their suggestion of hitting the Command key does not work. Neither does Shift-M, Command-D, Option-M, Shift-Option-Enter. Any other ideas?