I've recently gotten the GoG patched version (after having recently gotten it from my account on here again, "spring cleaning" of my data) and found that the old registry edit of forcing windowed mode is not working.

Is there another option to take?

Try this - http://sourceforge.net/projects/dxwnd/

http://sourceforge.net/p/dxwnd/discussion/general/thread/f1e3fd54/