Windows 8's uptake came unstuck last month and shoved into a forward gear for the first time since May, but the OS trailed Windows Vista's tempo of six years ago, according to data published Monday. Web analytics firm Net Applications' numbers for August put the combined user share of Windows 8 and 8.1 at 13.4 percent of the world's desktop and notebook systems, an increase of nine-tenths of a percentage point from July. That gain was the first since May and the largest since April, and followed two straight months of declines -- the first ever for the OS.