Acer, the world’s third-largest computer maker, more than halved its growth forecast for this year amid a weakening economy and a more cautious view toward Microsoft Corp.’s new operating system. The stock fell. Shipments for the full year will be unchanged to 5 percent higher than last year, compared with Acer’s earlier estimate of 10 percent growth, Kevin Lu, investor relations spokesman for the Taipei-based company, said by phone today. Acer, which posted its first loss on record last year after losing market share, is looking to Microsoft’s new Windows 8 operating system to spur sales of consumer PCs amid the popularity of Apple Inc.’s iPad. Distributors are now more conservative about building inventory of Windows 8 computers, while the global economy is weaker than what was expected in February when Acer provided its earlier forecast, Lu said today. Acer dropped 2.4 percent to NT$29.10 as of 12:36 p.m. in Taipei trading, headed for the lowest close since Aug. 26, while the benchmark Taiex index lost 0.1 percent. The stock has declined 17 percent this year, lagging a 1 percent advance in the Taiex. From gulfnews