If antivirus is not installed on a computer, it becomes vulnerable to virus attacks and malware infection, when it is connected to the internet. The antivirus scans the codes of all the files in the computer with the codes available in its database. If the code for any file matches the codes in the antivirus database, it is detected as malware and the antivirus takes further action to protect the computer from the identified malware. It is imperative to install an antivirus on the computer to prevent it against attacks from malware and viruses and protect it against data loss and damage. It becomes even more important if the computer is regularly connected to the internet. During the antivirus installation, it is important to ensure that installation and McAfee Activation Support Number of the antivirus are done systematically and the antivirus is regularly updated..