Viruses feat neatly into the malicious software type of computer software - malware is just a small type of malicious software program .
It's always funny to watch many Hollywood hacker picture and to see a virus on a pc monitor with a laughing skull or a voice message about how you've just been hacked . That's so much crap ! Real viruses - the really good ones - stay hidden . The arrive in e-mail attachments or hidden other programs and they stay hidden until it's time to attack . Computer viruses are very much like human viruses - they need someplace to live first and reproduce and then they appear when the time is right .
Once the virus is activated and has spread around your computer system then the damage phase will begin . Most viruses are written to activate on a specific trigger - a time , date or once the virus has infected x number of files . Once the trigger point is reached the virus then delivers its payload to your system.
This might be just annoying messages or it might trash your entire operating system and leave you staring at a blank screen . Once you've had this happen to you once it never happens again believe me .
Worms are another "type" of computer virus but they're just a little bit different . A worm is able to reproduce itself and move around networks without using other programs or software as hosts .
Worms are usually more damaging to networks of computers than to individual computers . Because they self-reproduce they can cause damage by overloading network resources . This overload can cause slowdowns on the network by taking up a lot of bandwidth on the network itself . Like viruses , worms are sometimes designed to carry a payload . This is done by using a 'backdoor' on the target system .
Back in the day computer viruses were spread mostly on floppy disks and this was bad enough . Then the Internet arrived and proved to be massively popular with everyone ( how wrong could Bill Gates be ? ) and viruses started spreading even more quickly by e-mail and downloaded files . A virus that used to take weeks or months to travel around the world was now able to infect computers all over the