Microsoft Windows

Verified Timeline

Lore & Background

The first version of Windows, Windows 1.0, was released on November 20, 1985 as a graphical extension for MS-DOS. Microsoft released Windows 95 on August 24, 1995, featuring pre-emptive multitasking, a completely new user interface with a novel start button, and 32-bit compatibility. On October 25, 2001, Microsoft released Windows XP, unifying the mainstream and NT lines of OS under the NT codebase. The company released Windows 3.0 on May 22, 1990, featuring streamlined user interface graphics and improved protected mode capability for the Intel 386 processor. Windows 95 quickly became a success, backed by what The New York Times called 'the splashiest, most frenzied, most expensive introduction of a computer product in the industry's history.'

Reader's Guide

Microsoft Windows has been the dominant operating system in the IBM PC–compatible market since the 1990s. Its significance lies in its role in popularizing graphical user interfaces for personal computers, starting with Windows 1.0 in 1985 and achieving broad commercial success with Windows 3.0 in 1990. Windows is sold both as a consumer retail product and to computer manufacturers, who bundle and distribute it with their systems. The product line has expanded into multiple families—Windows for personal computers, Windows Server for servers, and Windows IoT for embedded systems—each with editions tailored to different users, such as Home, Professional, Education, and Enterprise. Its legacy includes the transition from MS-DOS-based versions to the Windows NT kernel, which now underpins all active Windows families. Windows' main competitors are macOS and Linux for personal computers, and iPadOS and Android for tablets.

Did You Know?

• Windows 1.0 was released on November 20, 1985, as a graphical extension for MS-DOS, despite Microsoft having begun jointly developing OS/2 with IBM that same August.
• Windows 95 was backed by what The New York Times called 'the splashiest, most frenzied, most expensive introduction of a computer product in the industry's history.'
• Windows XP, released on October 25, 2001, unified the mainstream and NT lines of OS under the NT codebase.
• In March 2004, the European Union brought antitrust legal action against Microsoft, resulting in a judgment of €497 million ($613 million) and requiring new versions of Windows XP without Windows Media Player.
• Windows 3.0, released on May 22, 1990, featured streamlined user interface graphics and improved protected mode capability for the Intel 386 processor.

From a Traffic Counter to the PC's Operating System

Microsoft's origins trace back to two childhood friends, Bill Gates and Paul Allen, who in 1972 built Traf-O-Data, a small device for tracking automobile traffic. Their real breakthrough came when the January 1975 issue of Popular Electronics showcased the Altair 8800 microcomputer. Allen recognized the opportunity and proposed writing a BASIC interpreter for the machine. Gates contacted the manufacturer, Micro Instrumentation and Telemetry Systems, and confidently claimed a working product already existed. After a flawless live demonstration in Albuquerque in March 1975, the company was formally established on April 4, 1975, with Allen coining the name 'Micro-Soft.' By 1977 the firm had opened its first international office in Japan. The pivotal moment arrived in November 1980, when IBM selected Microsoft to supply an operating system for its upcoming Personal Computer. Microsoft acquired a CP/M clone from Seattle Computer Products, rebranded it as MS-DOS, and retained ownership rights after the IBM PC launched in August 1981. Because IBM copyrighted its BIOS but left the operating system unrestricted, rival manufacturers could build compatible machines running MS-DOS, cementing Microsoft's position at the center of the personal computing world.

Windows, the IPO, and a New Era of Wealth

Windows 1.0 debuted on November 20, 1985, as a graphical extension for MS-DOS, despite having begun jointly developing OS/2 with IBM that August. Just weeks later, on February 26, 1986, the company relocated its headquarters to Redmond, Washington, and on March 13 it went public on the NASDAQ. The subsequent surge in share price generated an estimated 12,000 millionaires among its workforce and created three billionaires, a phenomenon that made the offering one of the most consequential in corporate history. By 1990, the Federal Trade Commission was already scrutinizing the firm for its partnership with IBM, foreshadowing more than a decade of government legal battles. That same year Microsoft launched the Office suite, bundling applications like Word and Excel, and on May 22 released Windows 3.0 with a refined interface and improved protected mode capability for Intel 386 processors. The company then pushed forward with Windows NT, drawing heavily on its copy of the OS/2 code, which shipped on July 21, 1993 with a modular kernel and the Win32 API. The OS/2 alliance with IBM effectively collapsed, and both Office and Windows became dominant in their respective areas.

Leadership Shifts and the Road to Cloud and Gaming

Steve Ballmer took the CEO seat from Bill Gates on January 13, 2000 and steered the company through a period of aggressive expansion. Under his watch, Microsoft completed its then-largest acquisition with the purchase of Skype Technologies in 2011, introduced the Surface line in 2012 as its first in-house personal computer brand, and formed Microsoft Mobile through Nokia. In 2014, Satya Nadella assumed the CEO role and redirected the company's strategic center of gravity toward cloud computing. His tenure brought the landmark 2016 acquisition of LinkedIn and a sustained investment in the Xbox gaming ecosystem. In 2022 Microsoft formalized its gaming operations into a dedicated Microsoft Gaming division, and the following year it closed the purchase of Activision Blizzard, one of the most transformative deals in the industry's history. Since the 1990s the company had been diversifying well beyond its original software roots, and by the mid-2020s its portfolio spanned cloud infrastructure, enterprise productivity tools, consumer hardware, online services, and a major presence in video gaming.

Market Dominance, Product Ecosystem, and Persistent Criticism

Since the 1990s, Microsoft has held a commanding position in both the IBM PC-compatible operating system market and the office software space. Its most recognized products include the Windows family of operating systems and the Microsoft Office and Microsoft 365 productivity suites, whose headline applications—Word, Excel, and PowerPoint—remain staples of workplaces worldwide. On the hardware side, the Surface lineup of PCs and the Xbox console brand, supported by the Xbox network, anchor its consumer-facing offerings. Online services such as Bing search, the MSN portal, Outlook.com email, and the Microsoft Store round out its digital presence, while enterprise and developer tools like Azure, SQL Server, and Visual Studio underpin its business-to-business revenue. In April 2019, Microsoft became the third publicly traded U.S. company to cross the one-trillion-dollar valuation mark, and it consistently ranks among the most valuable public companies and brands globally. Yet this dominance has drawn sustained criticism: regulators and competitors have challenged its monopolistic practices, users and analysts have flagged shortcomings in usability, robustness, and security, and the company has faced public scrutiny over its role in providing services to Israel during the Gaza conflict.