Microsoft introduced the Windows operating system, first released in 1985.
Windows 1.0 was released on November 20, 1985. It provided a graphical environment that ran on top of MS-DOS and included programs such as a calculator, calendar, clock, control panel, and Paint. Early Windows was not initially a complete replacement for DOS.
Microsoft developed Windows after the growing popularity of graphical interfaces on personal computers. Later releases, including Windows 3.0 in 1990 and Windows 95 in 1995, greatly expanded its popularity and helped establish Microsoft as a dominant personal-computer software company.
Windows is sometimes confused with MS-DOS because the earliest versions depended on DOS. They were related but distinct products. Microsoft's other major businesses include enterprise software, cloud computing through Azure, gaming, and productivity applications such as Microsoft 365.