Microsoft to give away Windows 10, unveils hologram glasses

By Bill Rigby SEATTLE (Reuters) - Microsoft Corp will give away its upcoming Windows 10 operating system as a free upgrade to users of the most recent versions of Windows and Windows Phone, as the world's largest software company tries to retain customers in the mobile era. The action is a marked change for the company, which has always charged for new versions of Windows, one of its main profit drivers. "It's a necessary evil as CEO Satya Nadella and Microsoft have recognised the 'golden goose'