CALIFORNIA, USA: Microsoft Corp launched its new Windows 7 operating system on Thursday. Here are some significant dates in the history of Microsoft and its development of the world's predominant computer software.

1975 - Microsoft founded by Bill Gates and Paul Allen

1981 - IBM introduces its personal computer with Microsoft's

MS-DOS 1.0 operating system, which relies on typing commands

1983 - First version of Windows released

1985 - Windows 1.0 released, featuring bitmap display and use of mouse pointing device

1987 - Windows 2.0 released

1990 - Windows 3.0 introduced, features 16 colors and a new set of Windows icons

1993 - Windows NT 3.1 released, aimed at business computing market

Aug 24, 1995 - Windows 95 released, adds multimedia and mobile capabilities

June 25, 1998 - Launches Windows 98, aimed specifically at consumer market

Jan 13, 2000 - Steve Ballmer named Microsoft CEO

Feb 17, 2000 - Windows 2000 launched

2000 - Windows Millennum edition made generally available, aimed at home computer users with music, video and networking enhancements

Oct 25, 2001 - Windows XP launched, combines business and consumer operating systems

Jan 30, 2007 - Windows Vista launched

June 27, 2008 - Chairman and co-founder Gates retires from day-to-day role at Microsoft to spend more time on philanthropy at the Bill & Melinda Gates Foundation

Oct 22, 2009 - Windows 7 released.