Microsoft's chief executive Satya Nadella (pictured) says the tech giant wants to move from "people needing Windows, to choosing Windows, to loving Windows". That's a big ask. Windows 10 comes almost three years after the launch of Windows 8. That turned out to be a flaccid affair, leaving many Microsoft users annoyed at the radical overhaul of the layout and, in particular, the decision to ditch the start button menu.

The start button is back, but the new operating system enters a rapidly changing landscape. While Nadella is focused on mobile, a large cohort of Microsoft’s customers will download Windows 10 on a PC. And that’s a hardware market facing headwinds.

Figures published in the Wall Street Journal show PC sales have declined each year since 2012 and are forecast to fall again this year. PC shipments are down 21 per cent from a peak in 2011. Meanwhileorldwide shipments of smartphones have had another stellar quarter. According to research firm IDC, global shipments between April and June reached 337 million units, up nearly 12 per cent on the same quarter last year. Perhaps this is why Microsoft has opted to reboot its revenue model. The bulk of Windows revenue comes from hardware makers installing it on new PCs and businesses paying for multi-year licences. In contrast, Windows 10 is free to existing users of Windows 7 and 8. The strategy seems designed to put Windows on as many devices as possible and open up added revenue streams. Chief financial officer Amy Hood said the firm was looking to generate revenue by building search and gaming capabilities into the Windows 10 interface. It wants to be the go-to platform where app developers pitch their wares: not simply a home for apps reconfigured from variants built for Apple's IOS.

Big software hits of late have emerged from start-ups rather than software giants. Nadella wants these start-ups to develop their software for Windows 10.