http://www.microsoft.com/en-gb/security/pc-security/virus-whatis.aspx

http://en.wikipedia.org/wiki/Computer_virus

http://www.allaboutcookies.org/security/

http://www.wikihow.com/Secure-Your-PC

http://www.ehow.com/how-does_4579979_computer-virus-spread.html

http://support.microsoft.com/kb/129972