There are three common kinds of malware: worms, viruses, and Trojans.
Worms are the worst since they can function without human aid.
Malware is considered to be software that is malicious.
Like viruses, worms can copy themselves.
However, unlike viruses, worms are entirely self contained.
A virus needs to have a host program in order to spread while worms can propagate on their own.
Worms can be developed to do a lot of harm, such as corrupting programs and deleting files.
Most times worms will affect networks.
A network uses routers and servers to function.
The Internet is a huge organism of computer networks that all cooperate together.
A server is much like a PC but generally faster, with more resources, and with more storage.
Servers "serve" other computers by making certain resources available for more than one user.
A router is a server that is specialized but just uses different operating systems and hardware to move traffic on the network.
A worm can be put into a network and then can self copy.
It's this copy behavior that can cause a lot of damage.
Routers need to use memory and processor time and worms can cause them to become overwhelmed.
This can create a slow down on the network and instability.
A virus doesn't need to delete files before it does harm since they can cause the central processing unit (cpu) to be always busy.
This will leave no other resources for the other programs that need to run.
A worm can carry what is called a "payload".
A payload is other kinds of malware, such as backdoor programs and spyware.
Spyware is used to track your activities on the computer while a backdoor is a hidden point of access on your computer which can be used by hackers to steal information from your computer or to send spam.
The worst worm ever was known as "MyDoom".
This worm was first released in January of 2004 and was sent around by email that had a subject line that said "andy; I'm just doing my job, nothing personal, sorry".
The author of this worm was never found but some people think that the worm was created to attack SCO, a software company.
The email was programmed to hit the website of SCO with loads of Internet traffic, eventually reaching the Internet and causing a world wide Internet slow down.
For home computer users the payload of a worm is the worst threat.
A payload can be developed to manipulate your computer security by turning off your antivirus or by opening up ports in your computer.
A port is used by networking software to move data to and from the Internet.
When the ports are open data theft can occur or your computer files can be deleted.
De-Worming A firewall is one way that you can protect your computer from worms.
You can set up a firewall so that it will restrict traffic on the network as well as put a "cloak" over your computer.
If no one can see your computer it can't be used to spread worms across the network.
Worms, however, can be spread through attachments in email so you need to be careful when you're opening mail from sources that you don't recognize or when you're getting files that are unexpected.
Even with all these precautions your computer can be infected.
You might notice that your computer is acting slow or that it is rebooting itself.
As well, your access to the Internet can become slow.
If you think that your computer has a worm you need to scan it with antivirus software.
If the worm can't be removed you can find worm removal instructions on the Internet.