Microsoft Corps Windows 8 system has racked up more than 200 million license sales since its launch 15 months ago, according to Tami Reller, its head of marketing, lagging Windows 7 which sold 240 million within its first year. The latest Windows 8 sales figure, announced by Reller at a Goldman Sachs technology conference on Thursday, is the first that Microsoft has made public for more than six months. More worryingly for Microsoft, the number of people actually using Windows 8 is persistently low. Meanwhile, 48 percent are sticking with Windows 7 and 29 percent are still running Windows XP, which is more than a decade old.