Microsoft Windows is a piece of software called an operating system. An operating system does what its name implies: It operates your computer system, working in the background every time you turn on your PC. The desktop that fills your screen is part of Windows, as is the taskbar at the bottom of the screen and the big menu that pops up when you click the Start button.
If you’ve used a version of Windows prior to Windows 8, or seen someone else using Windows in the past, you might think that this new version of Windows looks a lot different—and you’d be right. Windows 8 introduced a completely different user interface to the operating system, and Windows 8.1 builds on that. The Windows 8/8.1 user interface is called the Modern interface, and it differs from the traditional Windows desktop.
In Windows 8.1, everything starts on the Start screen (the home screen full of tiles for different apps) and goes from there. The traditional desktop is still there (as an app, and used to run older software programs), but you’ll be spending most of your time with the new Modern interface and its tiled Start screen.