Despite valiant efforts to push its Windows licensees to adopt Vista and the forthcoming Windows 7, Microsoft has one again agreed to extend the option of selling Windows XP for use on new PCs for another year, through April 30, 2010. According to a source within Hewlett Packard, “Microsoft has granted the PC giant an extension to its existing rights to continue selling the nearly eight year old Windows XP on the company's business desktops, workstations, and notebooks in place of Windows 7 for another year,”  reports AppleInsider.