Scan Virus

Hi. Mac does not get viruses. There is no need to install antivirus software.

Usually antivirus apps do nothing for your Mac because there are no viruses that can infect Mac OS system.

You may find useful info and opinions in this thread:

i am new to Mac do i need antivirus software

Useful site that contains info about Mac threats: http://www.thesafemac.com/

Read Effective defenses against malware and other threats.

If you are having trouble with your Mac, describe the symptoms. Downloading and installing any "anti-virus" or "anti-malware" product would be the first step in a well-worn path to misery.