in full William Henry Gates III
born Oct. 28, 1955, Seattle, Wash., U.S.
U.S. computer programmer and businessman.
As a teenager, he helped computerize his high school's payroll system and founded a company that sold traffic-counting systems to local governments. At 19 he dropped out of Harvard University and cofounded Microsoft Corp. with Paul G. Allen (b. 1954). Microsoft began its domination of the fledgling microcomputer industry when Gates licensed the operating system MS-DOS to IBM in 1980 for use in IBM's first personal computer. As Microsoft's largest shareholder, Gates became a billionaire in 1986, and within a decade he was the world's richest private individual. Beginning in 1995, he refocused Microsoft on the development of software solutions for the Internet , and he also moved the company into the computer hardware and gaming markets with the Xbox video machine. In 1999 he and his wife created the largest charitable foundation in the U.S.