During a Q&A session with Microsoft’s Chris Liddell at Citi Annual Global Technology Conference, netbook question arose again. Liddell didn’t share how much Microsoft’s planning to charge PC for Windows 7 Starter or Windows 7 Home Premium, on low-end netbooks. (Microsoft charges about $15 per copy for XP on netbooks.) “Liddell reiterated Microsoft’s claim that 92% to 93% of netbooks’re now going out with Windows XP, not Linux. While Microsoft charges multiple hundreds of dollars for a new copy of Windows, Liddell said the actual cost’s $15. Here’s how he calculated: The average selling price for Windows (when figured across all versions) is $60 per copy, he said. The average user sticks with a particular version of Windows for four years. So the cost of Windows isn’t really $249 or even $99. It’s $60 divided by four, or $15 for a “one year experience.” And if you compare $15 to the cost of having to learn a new OS or port your apps to a new platform, Windows looks downright cheap,” Liddell said.