How to Upgrade to Windows 10 | WIRED
Windows 10 editions - Wikipedia, the free encyclopedia
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Product Keys and Activation -- MSDN Subscriptions
windows "n edition" - Google Search
"The N editions of Windows 7 allow you to choose your own media player and software required to manage and play CDs, DVDs, and other digital media files. If you choose to use Windows Media Player 12, downloading it, along with related software, is free."
(this is a result of EU antitrust settlement)