Hundreds of 15-inch PowerBook G4 owners are complaining about a flaw that causes white spots to appear on the laptop’s LCD display. Apple said in a statement on Friday that it is looking into the problem: “The new 15-inch PowerBook has been a big hit with customers since its introduction last month. However, some customers are reporting the appearance of faint white spots on their displays after using the system for a short period of time, and Apple is investigating these reports right now. Any customers experiencing this problem should contact AppleCare.” More than 650 owners have signed an online petition demanding that Apple address the issue.