Windows XP N
I believe the N stands for nothing as that is what it accomplishes. The main difference between the N version and a regular copy of XP is that N makes you download a media player. This new product was foisted on Microsoft by the European Competition Commissioner. (Now there is an oxymoron!) Microsoft was forced to sell it in Europe "as part of the punishment in the software maker's long antitrust battle with the European Union."
Here's the surprise: Nobody wants to buy it. Dell and Sony won't even offer to install it on their new PCs! Though I guess this comes as no surprise if you consider this is business as usual in Europe, bureaucrats in Brussels wasting tax payer money by issuing rulings that nobody cares about and which don't do anybody a lick of good.