While Satya takes over as CEO, co-founder Bill Gates is stepping down as chairman today and his new official title is technology advisor. "I'm thrilled that Satya has asked me to step up, substantially increasing my time at the company," says Gates in a video commenting on Nadella. "I'll have over a third of my time available to meet with product groups and it'll be fun to define this next round of products working together."
Nadella is a Microsoft veteran, having joined the company over 20 years ago. Born in Hyderabad,India in 1969, Nadella studied Electrical Engineering at the Manipal University before moving to the US to study computer science at the University of Wisconsin. He originally worked at Microsoft rival Sun Microsystems before heading to Redmond to work on research for Microsoft’s online services division. 

Click here to watch Satya Nadella's first interview as CEO :
http://www.youtube.com/watch?v=T8JwNZBJ_wI#t=43