mondo84: The GOG version installs the game into Windows rather than using DosBox, but
another user on the forum created a DOS interpreter that will use the game's directory files to load the DOS version.
http://www.sierrahelp.com/forums/viewtopic.php?f=7&t=3481 Then you can just run DOSBox in a window with a set resolution. Apparently it has some sound issues but you can give this a try.
camseyeview: so there is no way of doing it on windows?
To my knowledge, no. It may be possible by going into some of the game's configuration files, but I haven't heard of anybody doing this. At the time the game came out monitors had lower resolutions, so I guess it was just designed to run fullscreen.
But that DOSBox method might work, if you feel like giving it a try!