Originally Posted by CoramDeo
What is windowed mode?
It's the opposite of full-screen mode, that is it will use a window as its display surface (including window decorations). Start MAME with the option "-window" (or set "window 1" in mame.ini).

The default is "-nowindow" which means full-screen (or "window 0" in mame.ini).

A mind is like a parachute. It doesn't work unless it's open. [Frank Zappa]