Washington, March 15 -- Microsoft Corp co-founder Bill Gates, who made the company one of the world's most valuable technology firms, stepped down from the board on Friday to focus on philanthropic works related to global health, education and climate change. The billionaire and his wife Melinda run one of the world's largest charities, the Gates Foundation, which has billions in assets and funds global health programmes to combat disease and poverty. "Bill founded our company with a belief in the democratising force of software and a passion to solve society's most pressing challenges; and Microsoft and the world are better for it." Microsoft chief executive Satya Nadella said in a release. p15...