It's a sad fact that there are countless viruses, trojan horses and worms flying around the internet, looking for those unfortunate IT systems that are open to attack. 

What is a COMPUTER VIRUS?

A computer virus is a small software program that spreads from one computer to another computer and that interferes with computer operation. A computer virus may corrupt or delete data on a computer, use an e-mail program to spread the virus to other computers, or even delete everything on the hard disk.

What is a COMPUTER TROJAN HORSE?

A computer trojan horse is a destructive program that masquerades as a benign application. Unlike viruses, Trojan horses do not replicate themselves but they can be just as destructive. One of the most insidious types of Trojan horse is a program that claims to rid your computer of viruses but instead introduces viruses onto your computer.