Microsoft Windows, also called Windows and Windows OS, computer operating system (OS) developed by Microsoft Corporation to run personal computers (PCs). With the first graphical user interface (GUI) for IBM-compatible PCs, the Windows operating system soon dominated the PC market. About 90 percent of PCs run some version of Windows.
The first version of Windows, released in 1985, was simply a GUI offered as an extension of Microsoft's existing hard disk operating system or MS-DOS. Based in part on licensed concepts that Apple Inc. had used for its Macintosh system software, Windows, for the first time, allowed DOS users to visually navigate a virtual desktop by opening graphical "windows" displaying the contents of electronic folders and files clicking displayed a mouse button instead of typing commands and directory paths at a text prompt.
Subsequent versions introduced greater functionality, including native Windows programs for File Manager, Program Manager, and Print Manager, and a more dynamic user interface. Microsoft has also developed specialized Windows packages, including the network-enabled Windows for workgroups and the powerful Windows NT aimed at businesses. The 1995 consumer version of Windows 95 fully integrated Windows and DOS and offered built-in Internet support, including the World Wide Web browser Internet Explorer.
With the release of Windows XP in 2001, Microsoft unified its various Windows packages under a single banner, offering multiple editions for consumers, businesses, multimedia developers, and others. Windows XP abandoned the long-used Windows 95 kernel (core software code) in favor of a more powerful code base, offering a more practical user interface and improved application and memory management. The highly successful XP standard was superseded by Windows Vista in late 2006, which experienced a difficult launch and met significant market resistance, quickly gaining a reputation for being a large, slow, and resource-intensive system. In response to Vista's disappointing adoption rate, Microsoft released Windows 7 in 2009, an operating system that had a similar user interface to Vista's but was enthusiastically received for its noticeable speed improvement and modest system requirements.
Windows 8 in 2012 offered a Start screen with applications displayed as tiles in a grid and the ability to sync settings, allowing users to log on to another Windows 8 computer and use their preferred settings. In 2015, Microsoft released Windows 10, which came with Cortana, a digital personal assistant like Apple's Siri, and the Microsoft Edge web browser, which replaced Internet Explorer. Microsoft also announced that Windows 10 would be the last version of Windows, meaning that users would receive regular updates to the operating system, but no longer major revisions.