The chairman of Microsoft and one of the world’s richest men, Bill Gates,  stepped down from his job running the world’s largest software company. But Mr Gates’ fortune is at the root of his decision to leave his day job and concentrate on his charitable organisation, the Bill and Melinda Gates Foundation. He will remain as Microsoft’s chairman and work on special technology projects, but according to Mr Gates, great wealth brings great responsibility and his future work will include finding new vaccines and financing projects in the developing Mr Gates, who made his fortune through developing software for the personal computer, plans to devote his time to charity work. The son of a successful lawyer from Seattle, Mr Gates programmed his first computer at the age of 13.  Now 52, he still has boyish looks, but he is no longer the world’s richest man. He has been overtaken by the investor Warren Buffett and the Mexican telecom tycoon Carlos Slim.