Oct. 25, 2012: Steven Sinofsky, then-president of the Microsoft Windows group, delivers his presentation at the launch of Microsoft Windows 8.AP Photo/Richard DrewOct. 25, 2012: Microsoft CEO Steve Ballmer gives his presentation at the launch of Microsoft Windows 8.AP Photo/Richard DrewNot even his presumed heir apparent, who runs the software maker's Windows empire, can stop Ballmer as he pushes the company in a new direction.That was the underlying message of a power struggle that led to the abrupt departure of Steven Sinofsky, who oversaw the Windows operating system that has been the foundation of Microsoft's success.The fissure announced