Bill Gates surrounded by copies of Windows in 1986 and last November, accepting the Bambi award in Berlin.
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Bill Gates at the Milken Institute Global Conference in Beverly Hills, Calif., May 1, 2013.
Bill Gates demonstrates a Tablet PC to attendees of the Newspaper Association of America's conference on April 29. 2003
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Bill Gates appears on a video monitor in a CompUSA store in Vienna, Va. on August 24, 1995, Windows 95's launch day.
Left; AP; Darren McCollester / Getty
Left; Bill Gates in 1984 and; Bill Gates during commencement ceremonies at Harvard University June 7, 2007.
Bill Gates via Reddit
Bill Gates takes questions from Reddit users during an AMA (Ask Me Anything) session.
Bill Gates shows off his SPOT watch during his 2003 CES keynote.
Bill Gates brandishes a copy of Windows XP in Times Square during the XP launch on October 25, 2001
Bill Gates, surrounded by boxes with a now-ancient Microsoft logo in 1986
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Bill Gates, chairman of Microsoft
(l. to r.) Jason DeCrow / AP; Josh Reynolds / AP
Bill Gates (left) and Eli Broad
Bill Gates gives a baby an oral polio drop at a community health clinic in Andhra Pradesh
Bill Gates: Wants to pay his estate taxes
Bill Gates responds to the ruling by Judge Thomas Penfield Jackson
Microsoft co-founders Paul Allen and Bill Gates at the PC Forum conference in February 1987
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Warren E. Buffett, left, and Bill Gates, right, attend the opening ceremony of a new branch of Dairy Queen in Beijing on Sept. 30, 2010
Yuriko Nakao / Reuters
Microsoft Corp Chairman Bill Gates
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Microsoft chairman Bill Gates gives the keynote address at the Consumer Electronics Show on January 7, 2007, in Las Vegas, Nevada.
Microsoft chief Bill Gates
GREGORY HEISLER FOR TIME
GAME BOYS: Bill Gates and J Allard, who heads the Xbox technology team, take the 360 for a spin
GREGORY HEISLER FOR TIME
Bill Gates and J Allard, who heads the Xbox technology team, take the 360 for a spin
EVAN AGOSTINI / GETTY FOR TIME
Jim Kelly, Bill Clinton and Bill Gates conclude a lively conversation on a common cause
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Dwarfed by a game screen, Microsoft's Bill Gates and Steve Ballmer play Fight Night Round 3 as boxing announcer Al Bernstein calls the contest at the opening of the 2006 CES
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Former chairman of Microsoft and co-founder of the Bill and Melinda Gates Foundation Bill Gates, second from right, is pictured in central London, on June 11, 2009, during the launch of ONE's 2009 DATA Report, which tracks progress on the G-8 promises to Africa made in Gleneagles in 2005