Popup Blocker is the most powerful tool to stop annoying popup windows. It stops any annoying unsolicited pop-up windows including those popups when you are closing some web pages. It is extremely easy to use and you needn't add any 'popup list' for stopping any pop up windows. Clever--it only stops popup windows, never interferes with user's navigation. Funny--it plays sound and flash tray icon when it's working. Small--it consumes little system resource.