Hugh Pickens writes writes: "PC World reports that Windows XP lost more than 11 percent of its share from September to December 2011 to post a December average of 46.5 percent, a new low for the aged OS as users have gotten Microsoft's message that the operating system should be retired. Figures indicate that Windows 7 will become the most widely used version in April, several months earlier than previous estimates. Two months ago, as Microsoft quietly celebrated the 10th anniversary of XP's retail launch, the company touted the motto "Standing still is falling behind" to promote Windows 7 and demote XP and in July, Microsoft told customers it was "time to move on" from XP, reminding everyone that the OS would exit all support in April 2014. Before that, the Internet Explorer (IE) team had dismissed XP as the "lowest common denominator" when they explained why it wouldn't run IE9. The deadline for ditching Windows XP is in April 2014, when Microsoft stops patching the operating system. "Enterprises don't want to run an OS when there's no security fixes," says Michael Silver, an analyst with Gartner Research rejecting the idea that Microsoft would extend the end-of-life date for Windows XP to please the 10% who have no plans to leave the OS. "The longer they let them run XP, the more enterprises will slow down their migration.""