All organizations are at risk of “contracting” computer viruses, Trojans and worms15 if they are connected to the Internet, or use removable media (e.g., floppy disks and CD-ROMs), or use shareware/freeware software. The impact of a virus, Trojan, or worm can be as harmless as a pop-up message on a computer screen, or as destructive as deleting all the files on a hard drive. With any malicious code, there is also the risk of exposing or destroying sensitive or confidential information. There are two primary types of anti-virus programs available: those that are installed on the network infrastructure and those that are installed on end-user machines.