Microsoft says Windows head Sinofsky leaving

Sinofsky's departure comes just weeks after the Redmond, Wash., software company launched Windows 8, which represented a major overhaul of its ubiquitous computer operating system.

Company veteran Julie Larson-Green has been promoted to lead all Windows software and hardware engineering, Microsoft said. Tami Reller will take over responsibility for the Windows business while retaining her posts as chief financial officer and chief marketing officer.

The company did not say why Sinofsky is leaving.

In a statement, Microsoft CEO Steve Ballmer expressed gratitude for Sinofsky's contribution to the company. He indicated the need for the company to further integrate its array of offerings, which in addition to Windows includes services such as Bing, Skype and Xbox and a new tablet computer, as it begins what he called "a new era at Microsoft."

Ballmer said "it is imperative that we continue to drive alignment across all Microsoft teams, and have more integrated and rapid development cycles for our offerings."