whats the differnce between trojans VIRUSES parasites ect what do they all doTrojan Horse
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.


Viruses and Worms
A program or piece of code that is loaded onto your computer without your knowledge and
runs against your wishes. Viruses can also replicate themselves. All computer viruses are manmade. A simple virus that can make a copy of itself over and over again is relatively easy to produce. Even such a simple virus is dangerous because it will quickly USE all AVAILABLE memory and bring the system to a halt. An even more dangerous type of virus is one capable of transmitting itself across networks and bypassing security systems.

Since 1987, when a virus infected ARPANET, a large network used by the Defense Department and many universities, many anti-virus programs have become available. These programs periodically check your computer for the best-known types of viruses.

Some people distinguish between general viruses and worms. A worm is a special type of virus that can replicate itself and use memory, but cannot attach itself to other programs.

Hope this helps. By the way, these definitions are from http://www.webopedia.com This is a good site with definitions of computer-related terms. Good place to check to find out what something is.

Best...Larry