Try one of these free online scanners to see if your antivirus has been corrupted: http://www.carrona.org/malware.html
If you are infected, please follow the instructions pinned at the top of the malware forums located here: http://www.techsupportforum.com/f50/
If you are infected, please follow the instructions pinned at the top of the malware forums located here: http://www.techsupportforum.com/f50/