Julie Larson-Green, the Microsoft executive who co-led Windows development as recently as last summer and now heads the company's hardware efforts, will move to the group responsible for Office, where she once worked, according to an internal email obtained by the website GeekWire. Her change of jobs was likely triggered by promises made last September, when former CEO Steve Ballmer said that Stephen Elop, the then-CEO of Nokia, would rejoin Microsoft after the $7.4 billion acquisition of the Finnish company's handset business to head an expanded devices group at Redmond.