I mounted a computer monitor sideways so I could have a vertical cabinet. I was able to get the screen to rotate (am running Windows XP with AVGA2 card) correctly but when I launch games they are in windowed mode.

I selected the "start maximized" box in the general preferences but that did just that, maximize the box, not give me full screen. If I select FULL SCREEN on the MAMEUI GUI the program itself will enter full screen mode (pressing F11 will toggle this) but the games themselves are always windowed. What should I try to get this working correctly?
Thanks guys!