Microsoft Windows 1.0, seen here, was released in November 1985. Unfortunately for Microsoft, it failed to inspire -- especially when compared with the more user-friendly graphical user interface developed by Apple for the Macintosh.
Windows 2.0 was released two years later, in December 1987. The best that can be said for this incarnation was that Windows remained a work in progress.
The 1990 Windows 3.0 desktop workspace demonstrated that apparently three's a charm! The old adage about Microsoft needing three times to get it right was never more true. It offered better multitasking of older MS-DOS-based apps through the introduction of virtual memory. For the first time, Windows also garnered serious support from the software development community.
Windows 3.1 was released on April 6, 1992. The update included 32-bit disk access, more drag-and-drop icons, increased RAM and the classic game Minesweeper, as well as a media viewer, video file players and integrated sound and video with CD-ROM support.
Behold, the Start button -- a move that would stick around for years to come.
Windows NT was the first 32-bit version of Windows.
Released on June 25, 1998, Microsoft called Windows 98 the first version of Windows designed specifically for consumers. Windows 98 was also the last version based on MS-DOS.
A renamed version of Windows NT that added extra speed and stability. It was aimed at large businesses.
Windows Millennium Edition, or ME, was seen as a stop-gap release between Windows 98 and XP.
Windows XP was one of the most popular versions of Windows when it was released in 2001, and ditched the plain gray color scheme for blues and greens.
Windows Vista brought numerous improvements but also required beefier hardware and came with some stringent security that soured consumers and businesses alike.
Windows 7 brought a more refined look and a trimmed-down user interface upon its launch in 2009.
Microsoft made an aggressive move with Windows 8, which was released in October 2012. The new interface and tiled Start screen came with a steep learning curve that prompted a backlash from some users.
Windows 8.1 brought a handful of new features that make the OS work better on smaller tablets and let desktop users boot straight to the "desktop" mode.
Windows 10 arrived arrived two years after Windows 8.1, in 2015. Windows 10 brought a slew of new features like a reworked Start Menu and user interface, multifactor authentication security, compressed system files, the introduction to Microsoft Edge and more.
Windows 11 -- the newest version of Microsoft's operating system -- is expected to start rolling out on Oct. 5. Windows 11 will include new features like the ability to download and run Android apps on your Windows PC, as well as updates to Microsoft Teams, the Start menu and the overall look of the software, which is more Mac-like in design.