Anti-Virus Software is used to remove malicious programs from your computer. There are several types of malicious software known as Viruses, Trojan Horses and Worms below we have given a brief description of all three.
A major virus can cause alot of damage to your computer system, while some only have a small effect on your system. Most viruses are passed on by email or downloads and will only effect your system if you activate them. Most are passed on by people who do not know they have them and are in the form of an executable file, usually attached to an email.
The name says it all really. It can come in a package you think is safe, something like software you have downloaded or been given. When activated they can cause all sorts of problems, destroying or deleting files, adding icons to your screen or even opening a backdoor to allow hackers access to your confidential and personal information.
A worm is similar to a virus but is capable of traveling from one computer to another on its own by sending itself to everybody in your contacts in your email program, and then sends itself to everybody in your friends/contacts address books. The worms can replicate itself quite easily one hundred fold and will use that much power memory it can make computers and web/network servers useless. One of the most recent worms "Blaster Worm" tunnels into your system and allows others to control it.
Well now we have frightened you all to death and you are promising never to go on the internet again, don't worry they are all easily avoidable.
First you must download and install a Anti-Virus Program. Install it and run FULL scan. This may take awhile depending on the size of you hard drive. The Anti Virus Program will then monitor your system and incoming emails for known threats.
Second make sure you update your Windows system by going to Tools/Windows Update on your web browser. This will add security fixes to your operating system for any new dangers that Microsoft have discovered.
Third never open a file attached to an email unless it comes from a known source and you are expecting it.
Forth never click a popup window that tells you you have register problems or offering a free scan. just shut the window down using the cross in the top right corner. If it hasn't got one press "Ctrl+W" at the same time on your keyboard it should then close the window.
If you follow the above you should greatly reduce the risk of your system being infected.