**Microsoft Windows** is a family of [[Proprietary software|proprietary]] [[Operating system|operating systems]] developed and marketed by [[Microsoft]], designed primarily for [[Personal computer|personal computers]], [[Laptop|laptops]], [[Workstation|workstations]], and [[Server (computing)|servers]]. First introduced in November 1985 as a [[Graphical user interface|graphical user interface]] extension for [[MS-DOS]], Windows has evolved into the dominant desktop operating system worldwide, holding a market share consistently exceeding 70 percent of personal computer installations globally. The Windows family encompasses consumer editions including [[Windows 11]] and [[Windows 10]], server editions under the [[Windows Server]] brand, and specialized variants for embedded and enterprise environments. Microsoft Windows traces its origins to the partnership between [[Microsoft]] and [[IBM]] in the early 1980s, during which Microsoft supplied [[MS-DOS]] as the operating system for the [[IBM Personal Computer|IBM PC]]. Early versions of Windows, including Windows 1.0, 2.0, and 3.x, ran as graphical shells atop MS-DOS and achieved significant commercial success, particularly [[Windows 3.1]], released in 1992. The architecture shifted with [[Windows NT]], introduced in 1993, which provided a fully independent [[32-bit computing|32-bit]] operating system with a new kernel designed for stability and security. The NT kernel lineage merged with the consumer Windows line beginning with [[Windows XP]] in 2001, which unified the previously separate consumer and business product lines and became one of the most widely deployed operating systems in history. Subsequent major releases have included [[Windows Vista]], [[Windows 7]], [[Windows 8]], [[Windows 10]], and [[Windows 11]], each introducing architectural changes, interface redesigns, and new security and productivity features. Windows derives a substantial portion of its commercial significance from its integration with Microsoft's broader software ecosystem, including [[Microsoft Office]], the [[Active Directory]] directory service, and [[Microsoft Azure|Azure]] cloud services, as well as its historically dominant position in enterprise environments. The [[Windows Registry|Windows registry]], [[NTFS]] file system, and [[Windows API|Win32 API]] have established deep compatibility dependencies that have entrenched the platform across enterprise and consumer computing. Microsoft has faced significant [[Antitrust law|antitrust]] scrutiny over its handling of Windows' market position, most notably in the [[United States v. Microsoft Corp.|United States v. Microsoft]] case of 2001, which found the company had engaged in anticompetitive practices related to its [[Internet Explorer]] browser. More recently, Windows has been extended to support [[ARM architecture|ARM]]-based processors and deeper integration with [[Microsoft Azure|cloud]] services and [[Artificial intelligence|AI]] capabilities, reflecting Microsoft's strategic shift toward platform and services revenue.