Microsoft Corporation

Established on April 4, 1975 to develop and sell BASIC interpreters for the Altair 8800, Microsoft rose to dominate the home computer operating system (OS) market with MS-DOS in the
mid-1980s, followed by the Microsoft Windows line of OSs. 

History
Paul Allen and Bill Gates (respectively) on October 19, 1981 in a sea of PCs after signing a pivotal contract. IBM called Microsoft in July 1980 inquiring about programming languages for its upcoming PC line; after failed negotiations with another company, IBM gave Microsoft a contract to develop the OS for the new line of PCs.
Following the release of the IBM PC in August 1981, Microsoft retained ownership of MS-DOS;
 Due to various factors, such as MS-DOS's available software selection, Microsoft eventually became the leading PC OS vendor.

Microsoft released Microsoft Windows, a graphical extension for MS-DOS, on November 20.
Microsoft moved its headquarters to Redmond on February 26, 1986, and on March 13 the company went public;
the ensuing rise in the stock would make an estimated four billionaires and 12,000 millionaires from Microsoft employees.
Microsoft introduced its office suite, Microsoft Office, in 1990 - applications, such as Microsoft Word and Microsoft Excel;
On May 22 Microsoft launched Windows 3.0 with a streamlined user interface graphics and improved protected mode capability for the Intel 386 
processor.…