Window mode

From NWNWiki

To run the Neverwinter Nights player or DM client in window mode, edit nwn.ini (found in the NWN directory):

[Display Options]
FullScreen=0
AllowWindowedMode=1

The desktop resolution should be greater than NWN's resolution (for example, desktop at 1024x768 and NWN at 800x600). Otherwise, NWN will ignore its resolution setting and run at 800x600 instead.

It is also possible to switch between full screen and windowed mode while the game is running, by using the Alt-Enter key combination.