The Apple / Microsoft ad war keeps escalating — while Apple continues to insist that John Hodgman is the human representation of all PCs, Microsoft is taking its populist approach to the streets. Very specific streets, actually — it’s placing “I’m a PC” recording booths outside of Apple stores

[From Microsoft placing "I'm a PC" recording booths outside Apple stores - Engadget]

So this is actually about protecting the hardware vendors and their own sweet pre-loaded arrangements, No one buys Windows, do they? They buy a new machine and that’s that.