Microsoft Corp ( MSFT.O ) said sales of its flagship cloud product doubled in its first quarter, propelling earnings above analysts' estimates and sending its shares to an all-time high, breaking past a level hit in 1999 at the peak of the tech stock bubble. The company's shares have doubled since August 2013 with Chief Executive Satya Nadella restoring investor confidence by focusing on mobile and cloud computing rather than PCs. Long known for its Windows software, Microsoft has shifted focus to the cloud where it is dueling with larger rival Amazon.com Inc ( AMZN.O ) to control the still fledgling market. Its jump in revenue underscores how businesses around the world are turning to new applications in the cloud and leaving once critical software programs and other hardware in the dust. Shares of Microsoft rose as much as 6.2 percent to $60.79 in after-hours trading. They later pared gains to $60.43, still adding nearly $25 billion to its market value. ...