Apple virtually dominated US retail computer sales in October, the NPD Group said in a report issued Friday. The new iMac, particularly the 21.5-inch model, was the top-selling desktop for the month while the 13-inch MacBook Pro was the leader in notebooks for the same period. The Mac creator in each case had multiple entries in the top 10 of each category, with the 27-inch iMac in third place for desktops while other MacBook models were eighth, ninth and tenth in notebooks.