The ongoing Internet-security freakout for anybody using Windows keeps getting worse. Every other week yet another part of the online world gets a warning label slapped on it -- downloads, e-mail attachments, instant-messaging file transfers and now Web pages themselves. "Browser hijacking" is as bad as it gets: Like the Blaster worm, this form of trickery can take over your software silently and invisibly. Typically, users discover what has happened only after the actual hijacking: Their Internet Explorer home page and Web searches have been switched to strange sites, a flock of pop-up windows follows them around, their lists of favorite sites have become a catalogue of porn purveyors -- and none of these changes can be undone without tedious debugging.