For Notepad, unless I don't get your question:
Just run Notepad and minimize it before you run NWN. When you want to get at it, either hit Alt+Tab to go from NWN to Notepad and vice-versa or Alt-Entr to put NWN in windowed mode, that way you'll see your desktop
I have Notepad open most of the time I play..bleeming price list *grumbles*....and it never caused me a crash.