Try to use AdwareMedic (http://www.adwaremedic.com/index.php).
AdwareMedic should be able to remove it.
Malware and a virus are not the same thing.
Probably because it's not a virus.It did NOT catch this virus.
Updated ClamX to the latest virus definitions.
It's not a virus. It's adware, which is a different animal. Macs are not immune to malware, but no true viruses exist in the wild that can run on Mac OS X, and there never have been any since it was released over 12 years ago. The only malware in the wild that can affect Mac OS X is a handful of trojans, which can be easily avoided by practicing safe computing (see below). 3rd party antivirus apps are not necessary to keep a Mac malware-free, as long as a user practices safe computing, as described in the following link.Updated ClamX to the latest virus definitions. It did NOT catch this virus.