It works fully automatic and in the background and the only way to notice that a popup window has been closed, is if you choose to activate the sound notification which will sound every time a popup is closed. Main Popup Assassin Pro features: - Popup Assassin Pro is very fast and small; - Works best at blocking popup ads when using Internet Explorer; - Kills unwanted popup ads before they open; - Configure sites to block; - Allows to open any killed window from Popup Assassin Pro log; - Play different sounds when ads are blocked; - Runs in the system Tray. The Popup Assassin Pro blocks Popups before they can even start to download. This prevents popup ads from stealing bandwidth or locking up your browser with multiple windows opening.