A computer virus is a computer program that can infect your computer system by executing itself without your permission or knowledge and run against yours wishes. Viruses can also replicate itself to maximize the infection.

A virus can affect the normal functioning of the computer in many ways. Some viruses may display only a message on the screen whereas others may slow-down your PC may cause extensive damage to your system. For instance, they may change computer files so that programs do not work properly or even stop working. They can also erase files or even format your hard disk and crash the system. Viruses are also easily spread by carrying it on a removable medium such as floppy disk, USB drive or CD. Computer viruses are most easily spread by attachments in e-mail messages or by instant messaging messages.



The following are some primary indicators that a computer may be infected:

  • The computer runs slower than usual.
  • The computer stops responding, or it locks up frequently.
  • The computer crashes, and then it restarts every few minutes.
  • The computer restarts on its own. Additionally, the computer does not run as usual.
  • Applications on the computer do not work correctly.
  • Disks or disk drives are inaccessible.
  • You see unusual error messages.
  • An antivirus program is disabled for no reason. Additionally, the antivirus program cannot be restarted.
  • An antivirus program control be installed on the computer, or the antivirus program will not run.
  • A program disappears from the computer even though you did not intentionally remove the program.
Antivirus software is a computer program that defects, prevents, and takes action to disarm or remove malicious software program, such as viruses and worms. You can help protect your computer against viruses by using antivirus software, such as Norton Antivirus, Avast Antivirus, McAfee, Kaspersky, etc.

To protect your computer against viruses, follow these steps:

  • On the computer, turn on the firewall.
  • Keep the computer operating system up-to date.
  • Use updated antivirus software on the computer. 
  • Use updated antispyware software on the computer