While Microsoft claims it’s sold 40 million Windows 8 licenses in the month since launch—a more rapid pace than Windows 7—new data from research firm The NPD Group suggests that isn’t helping sales of actual Windows devices, which, in its estimation, are down 21 percent from last year. Desktops dropped 9 percent year-over-year, while notebooks fell 24 percent. “After just four weeks on the market, it’s still early to place blame on Windows 8 for the ongoing weakness in the PC market,” Stephen Baker, vice president of industry analysis at The NPD Group, wrote in a Nov. 29 statement attached to the data.  “We still have the whole holiday selling season ahead of us, but clearly Windows 8 did not prove to be the impetus for a sales turnaround some had hoped for.” The NPD Group claims that 58 percent of Windows devices sold in the last month are running Windows 8, comparing it to “the 83 percent [of devices] Windows 7 accounted for four weeks after that launch.” Despite Windows 8’s tablet-optimized Start screen, which features colorful tiles linked to applications (the better to tap with a finger, rather than click with a mouse), tablets running the operating system represent a mere 1 percent of sales to date. The operating system also offers the “traditional” desktop interface, accessible via one of those Start screen tiles. The average selling price (ASP) of a Windows machine has also jumped “significantly” this year, in the firm’s estimation, from $433 to $477. That could be due in part to touch-screen laptops, which generally retail at a premium to their non-touch siblings. “The strong performance of Windows 8 notebooks with touchscreens, where Windows 8 truly shines, offers some reason for optimism,” Baker wrote. “These products accounted for 6 percent of Windows 8 notebook sales at an average price of $867 helping to re-establish a premium segment to the Windows consumer notebook market.” Microsoft is depending on Windows 8 to help maintain its dominance of traditional operating systems while making inroads into the tablet market, which is dominated in large part by Apple’s iPad and various Google Android devices. However, the dual interface has attracted criticism from some quarters, including noted usability experts.