Microsoft's release of its new Windows 7 operating system is expected to increase demand for personal computers only slightly, Chief Executive Steve Ballmer in Munich "There will be a surge of PCs but it will probably not be huge," Ballmer said in answer to a question at a news conference about the likely effect on the market of the new system, which will replace the unpopular Vista. Major new software updates from Microsoft, whose Windows operating system runs about 90 percent of the world's PCs, are in general eagerly awaited by computer makers who hope for a sales boost. Ballmer reiterated he saw the technology sector returning to growth only slowly, and said it would take time to reach pre-recession levels.