1985

 Microsoft released first version of Windows – Windows 1.0, which allowed PC users to shift from MS Dos to Windows operating system.

1987

 Windows 2.0 was released. It had enhanced features such as improved processing speed, expanded memory, inter application capabilities through Dynamic Data Exchange (DDE), which gave user control to screen layout, use keyboard combinations and overlap windows.

1990

 Windows 3.0 was released. Hailed as the first mainstream computing platform. It came with a Program manager, File manager, Print manager and improved windows icons.

1993

 Windows 3.11 with domain networking support was released. With this release, Windows became an integral part of client/server evolution. Windows for workgroups operated in LAN, on stand-alone PCs and laptops.

1993

 Windows NT 3.1, which for first time combined support to client/server business applications and personal productivity applications, was released. It came with new features like multitasking scheduler for Windows-based applications, integrated networking, domain server security, and support for multiple processor architectures. Windows NT was targeted at business users and was made available in desktop and server versions initially. In late 1993, Microsoft released Windows NT workstation 3.5 supporting OpenGL graphics standards which made possible high-end applications in software development, engineering, financial analysis and critical business-related tasks. Microsoft's first Windows Server operating system Windows NT Advanced Server 3.1 was released. It was promoted as an application server for Novell Netware, Banyan VINES and Microsoft networks.

1994

 Windows NT Server 3.5, which was built on 3.1 version with increased processing speed and improved connectivity to other systems, was released. It provided new administration tools, client software configuration, auto-reboot and dump facility and remote access capabilities.

1995

 Release of Windows 95 Hailed as the successor to Microsoft's existing desktop operating systems – Windows 3.1, Windows for Workgroups and MS-DOS. Win 95 came with integrated 32-bit TCP/IP stack for Internet support, dial-up networking and plug & play capabilities that enabled users to install hardware and software easily. It also offered multimedia capabilities with powerful features such as mobile computing and networking. Microsoft released Windows NT Server 3.51, which enabled users to manage Client Access Licenses (CAL) for the Microsoft Backoffice family of server products.

1996

 Microsoft released Windows NT Workstation 4.0. It was upgraded for a business desktop o/s, and included the Windows 95 user interface, improved networking support and provided easy access to Internet and corporate intranets. Windows NT Server 4.0 with faster file and print management services, robust application support, integrated web server and complete tools for developing and managing intranets, was also released.

1997

 Windows NT Server 4.0, Enterprise Edition, with additional features to appeal to large corporate customers with mission-critical requirements, was released.

1998

 Microsoft released upgrade of Windows 95 – Windows 98 (designed specifically for individual customers). It opened and closed applications faster and supported reading of DVD discs and Universal Serial Bus (USB) devices. In October 1998, Microsoft announced that initials NT would be removed from Windows NT and announced the next major version of the o/s – Windows 2000. Microsoft released Windows NT Server 4.0, Terminal Server Edition, which came with a multi-user core, enabling it to host multiple and simultaneous client sessions, and a remote desktop protocol allowing communication between server and Windows-based client software.

1999

Second edition of Windows 98 called Windows 98 SE, was released, with Internet Explorer 5.0 and Microsoft Windows NetMeeting version 3.0-conferencing software. Windows 98 SE also provided the user with device drivers that worked with the Windows NT business operating system.

2000

Windows Millennium Edition was released. It offered users music, video and home networking enhancements. Windows 2000 Professional was also released. It was an upgrade to Windows NT 4.0 and was designed to replace Windows 95, Windows 98 and Windows NT workstation 4.0 on business desktops and laptops. Microsoft released three server versions of Windows 2000 providing scalability, reliability and manageability.

2001

Windows XP was released with the objective of unifying desktop operating systems. It was available in two versions – Windows XP Professional and Windows XP Home. With Windows XP, Microsoft was able to merge its two windows operating systems for individual consumers and businesses.

2002

Windows Server 2003 was launched to meet the requirements of all types of businesses. It incorporated Microsoft .NET Framework, allowing developers to create XML web services. It was released in four versions: Standard Edition, Enterprise Edition, Datacenter Edition and Web Edition.