Research firm Current Analysis Incorporated has concluded that Windows Vista spurred a 67% increase in personal computer sales at U.S. retail stores in its first week (ending Saturday) on the market. In terms of units sold, Hewlett-Packard was the top PC seller and Gateway took second place. (Dell may be the world"s second-largest PC maker, but the company wasn"t included because it doesn"t sell through stores). Microsoft began selling Vista in stores on January 30 after releasing it to some businesses on Nov. 30. Analyst Samir Bhavnani said the increase in the first week "compares very favorably" with the first week Windows XP was on sale in 2001. Kevin Kutz, Microsoft Windows client communications director, naturally said the company is "pleased with the initial response to Windows Vista."