Anti-virus software
From Conservapedia
Anti-virus software protects a computer from viruses and malicious software (malware) that can destroy data, slow a computer's performance, cause a crash, or even allow spammers to send email through your account, such as spam, or other viruses to others on your mailing list by searching a computer's hard disk for programs and comparing it against a known set of malicious software and deleting or quarantining suspicious items and software. [1].
