"This screen shot shows a command prompt from Cortana, Windows phone software's virtual assistant. With Cortana, Windows catches up with Apple's iOS and Google's Android in a major way. Microsoft takes some of the best parts of Apple's and Google's virtual assistants and adds a few useful tools of its own. The result is Cortana, named after an artificial-intelligence character in Microsoft's ""Halo"" video games. (AP Photo) Photo: Associated Press / Associated Press contributed"