Antivirus programs are widely used by the people to ensure protection, safety and security of files and folders, database and software programs. The various methods used for protection and elimination of viruses and other malicious software programs are discussed in this article. The first approach of the antivirus program is called as dictionary search approach. In this dictionary search approach the antivirus program checks the files and folders to find a matching program that is available in the data list of the antivirus software program. If a match is found then the system is said to be affected by virus. In such case the antivirus program alerts the user about the virus and the operations to be performed on the viruses. Another approach called as suspicious behavior or misbehavior approach. In this kind of approach the antivirus program keeps track of the various functions performed by the software programs of a computer system. If there is any deviation in these functions or a program is functioning in a manner which is vulnerable to other programs the user again receives an alert message from the antivirus program seeking what operation to be performed on the specific program. These antivirus programs have the ability to identify the location of the hidden files in a computer and scan them to ensure weather the particular file is affected or not. The operation of virus removal by antivirus program is classified into three. First is to repair the infected file to remove viruses. Second is the file quarantine process which makes the infected files inaccessible to the users. The third method is removal of infected files. The best way to prevent virus attacks and enable system protection is to allow only authorized and familiar programs to run in our computer and by avoiding unwanted and new installations from pop-up windows during browsing.