The Windows operating system is by far the best-selling for desktop computers and laptops; however, Microsoft has not yet had much impact in the mobile device market. Experts now forecast that the Microsoft OS will be the second bestselling for mobile devices by 2015, with Android at the top and Apple’s OS moving from second to third.

Microsoft’s next operating system ‘Windows 8’ is going to focus far more around touch-screen devices. Windows 8 will be released later in 2012.

Microsoft CEO Steve Ballmer: “And yet, as we look forward to the next generation of Windows systems, which will come out next year, there’s a whole lot more coming. As we progress through the year, you ought to expect to hear a lot about Windows 8. Windows 8 slates, tablets, PCs, a variety of different form factors.”

The graph below shows projections from Market Intelligence Company IHS iSuppli: