On November 26, 1976, Gates and Allen registered the "Microsoft" trademark. They once considered calling the company "Allen & Gates Inc." (Allen & Gates Inc.), but later decided to change it to "Micro-Soft" (Note: the English abbreviation of "Micro Software"), and The English hyphen in the middle of the name is removed. Allen was 23 and Gates was 21 at the time.

On January 1, 1979, Gates moved Microsoft's headquarters to Bellevue, Washington.

On August 28, 1980, Gates signed a contract with IBM and agreed to develop an operating system for IBM's PCs. He then purchased an operating system called QDOS for $50,000. After slightly improving it, he renamed the product DOS, and then licensed it to IBM for use.

In 1982, during its first year on the market, Gates licensed the MS-DOS operating system to 50 hardware manufacturers.

On November 10, 1983, the Windows operating system made its debut. This product is an evolved version of the MS-DOS operating system and provides a graphical user interface.

In April 1994, Gates appeared on the cover of Wired magazine for the first time.