November 20, 2010 marketed the 25th birth anniversary of Microsoft Windows, the world's most popular operating system.

The process of developing Windows began in 1981, but the project encountered repeated delays and could be finally released in late 1985 as Windows 1.0. At that time, Windows had to run on the top of DOS, and only a few applications were written for it.

Graphics painting program Paint and the Notepad text editor were among the handful of apps that were available with the operating system.

At the time of its launch, Windows were known only to a few, but eventually it emerged as the foundation of the strong empire of Microsoft.

An extract from the Windows 1.0 press release reads, "Microsoft Windows extends the features of the DOS operating system, yet is compatible with most existing applications that run under DOS.”

Two years later in 1987, the company released Windows 2.0 which featured ability to overlap app Windows and improved memory use. It required 512KB or more of memory. Windows became world’s dominant operating system after the released of Windows 3.0 and Windows 3.1 in 1990 and 1992.

Microsoft’s current desktop operating system is Windows 7, which was released in October last year. Windows 7 OS features ‘Aero’ interface and a number of enhancements that fixes the shortcomings of Windows Vista.