When I get a URL wrong at the top level (I don't think this is a 404 message but don't know the right name), my firefox browser redirects me to ask.com. How do I remove or customise this functionality? There's nothing obvious in the options dialogue and google isn't being helpful - probably because I don't know the correct name for the error!
Cheers.
EDIT: Windows, Firefox 3.0.14. Not malware, I think I accidentally installed it with realplayer or something.