Microsoft Windows celebrated its 40th anniversary on November 20, 2025. The journey began with the launch of Windows 1.0 in 1985, designed as a graphical layer atop MS-DOS, requiring a graphics card and 256KB of RAM. Subsequent releases included Windows 2.0 in 1987, Windows 3.0 and 3.1 in 1990 and 1992, respectively, which introduced significant features like a 3D-styled interface and popular games. Windows 95, launched in the mid-1990s, introduced the Start menu and taskbar, selling over seven million copies shortly after its release. The late 1990s and early 2000s saw the introduction of Windows 98, Windows 2000, and Windows XP in 2001, which was noted for its stability. Windows Vista was released in 2007, followed by Windows 7 in 2009, and Windows 8, which faced user backlash. Windows 10 was launched in 2015, adopting a Windows-as-a-Service model, and Windows 11 continues to evolve with new design and hardware requirements.