Gates was born in Seattle on Oct. 28, 1955.Using his school computer, Gates created a version of tic-tac-toe that people could play against the computer.Paul Allen met Gates at the Lakeside School in Seattle and founded Microsoft with him in 1975.
Windows hit the market in April 1985.
In March 2009, Forbes magazine estimated Gates' net worth at $40 billion. And that's down $18 billion from the previous year.
Gates officially stepped down at Microsoft in July 2008 to concentrate on the foundation, which had an endowment of $27.5 billion in April 2009.
Melinda was working for Microsoft when she encountered Gates at a press event in 1987.
Which billionaire helped Gates propose to Melinda?
In 1993, Gates surprised Melinda by flying her to Omaha, Neb., Warren Buffett's hometown. Buffett arranged for a jewelry store to be opened so they could buy a ring.