I'm sorry I won't be of much help, but... I'm fairly surprised that anyone would prefer to have NWN installed without expansions.
I mean, there are games in which expansions drastically change gameplay itself (mostly MMOs), so it's understandable how some would prefer a version without expansions or with only some of them in this case.
But Neverwinter Nights? Expansions mostly add new stuff to the game with little to no changes made to its base gameplay and graphics. Possibly the only gameplay alteration I can think of are Appraise checks for the original campaign's NPC merchants. Aside from this, everything is pretty much the same if you simply stay away from the newer content.
I don't know what's the reason you'd prefer the original game, but I advise you to stick to the expansions.