Microsoft created Windows, whose first commercial version launched in 1985, helping the company become one of the world's largest by market capitalization.
Windows 1.0 was released on November 20, 1985. It provided a graphical operating environment that ran on top of MS-DOS and included programs such as Paint, Calculator, and Notepad.
Bill Gates and Paul Allen founded Microsoft in 1975. The company first became prominent through software for personal computers, then expanded into Office, Azure cloud services, Xbox, enterprise software, and professional networking through LinkedIn.
Windows 1.0 was not a completely separate operating system in the modern sense; it was an environment layered over MS-DOS. Microsoft also uses the spelling “Microsoft,” not “MicroSoft,” in its official name.