Three years after Microsoft redeemed for the sins of Vista with the launch of Windows 7, another new Windows is upon us. Quite unlike its conservative predecessor, Windows 8 represents a huge departure from the way things used to work. A touch-based “Modern UI” interface now lies at the heart of the Windows experience, which brings a wave of tablet hardware to go along with it. Here’s everything you need to know about the tectonic shift the Windows universe is undergoing – and where it will take us.