Microsoft (MSFT) on Thursday officially launched its Windows 8 operating system at a media event in New York City. Steven Sinofsky, president of the company’s Windows and Windows Live division, noted that a record 1.24 bilion hours of extensive public testing that spanned across 190 countries was conducted on the platform. He added that there are now more than 1,000 certified Windows 8 PCs available and that the company’s ARM-centric Windows RT operating system supports more than 420 million devices such as printers, mice and keyboards, many of which connect to the platform right out of the box. The executive also announced that Microsoft sold 670 million Windows 7 licenses, and its SkyDrive services now store more than 11 billion photos, over 550 million documents and a total of 14 petabytes of data, which is growing at a rate of 2 petabytes per month.