"Input Not Supported"

Yup, I set my game to a resolution that's out of my monitor's range.

Is there anyway to change it back? Because I can't play the game now as I do not have a screen.

hold ctrl+alt+schift while launching guild wars will reset the screen resolution to 800x600

Thanks. Got it sorted myself a different way though.

Anyone else who has this problem, just hit Alt+Enter and change your resolution from there.

Alt+Enter puts you into Window mode.

Alt+Enter is a "standard" shortcut for switching between full screen and windowed modes - it's easy to not think of windows shortcuts when you're playing a game ^^