DisplayFullScreen Property [Excel 2003 VBA Language Reference]
True if Microsoft Excel is in full-screen mode. Read/write Boolean.
Full-screen mode maximizes the application window so that it fills the entire screen and hides the application title bar. Toolbars, the status bar, and the formula bar maintain separate display settings for full-screen mode and normal mode.
This example sets Microsoft Excel to be displayed in full-screen mode.
Application.DisplayFullScreen = True