How does antivirus software work?
An antivirus software program is a computer program that can be used to scan files to identify and eliminate computer viruses and other malicious software (malware). When a virus or sign of infection is found, the antivirus software alerts you to its presence. If a computer is running without an antivirus program, the virus may delete files or even other programs, alter the way your computer operates or stop it from working altogether. Computer viruses are often spread by attachments in email messages or instant messaging messages. That is why you should be cautious when opening email attachments unless you know who it's from.
Most antivirus software programs offer three ways of protection
Real-time protection - The product alerts you when malware, spyware, or potentially unwanted software attempts to install or run on your computer.
Scanning options - You can use the product to scan for threats, viruses, spyware, and other potentially unwanted software that might be installed on your PC, to schedule scans on a regular basis, and to automatically remove any malicious software that is detected during a scan.
Detection - Should malicious software be detected on your computer, certain actions will automatically be taken to remove the malicious software and protect your computer from potential further infection. Once the malicious software is removed, the product may also reset some Windows settings (such as your home page and search provider).