You should worry about computer viruses because when they arrive on your hard drive, they are there to cause harm. Exactly what they do to your computer depends on the type of virus. Here are some of the symptoms recorded:
Problem starting the computer
File disappearance or file size changes
Strange sounds and graphics appearances
Unpredictable program shutdown
Very slow boot up
What is a virus?A virus is a piece of code or computer program purposefully written to replicate itself and spread across computers and networks to disrupt the computing operations. Viruses infect your applications by attaching themselves to your executable programs. They come to your computer through the internet, email, and downloaded files.
Some other harmful programs similar to viruses are:
Worms — A worm is similar to a virus in terms of self replicating itself but it does not need to attach itself to another program to propagate.
Trojans — A Trojan is a malicious program designed to hide itself on your hard drive to harm your data. Unlike a virus, a Trojan Horse does not replicate itself and does not appear as an illegitimate software program.
Backdoor Trojans — As the name indicates a Backdoor Trojan is designed to allow other computer users to gain access to your computer across the internet.
Examples of viruses, worms and Trojans released in the past :
Bugbear-D — This worm was designed to record passwords and keystrokes of the user and send them back to the virus writer.
DLoader-L — This Trojan arrived through e-mail and was designed to attack websites.
Chernobyl (CIH) — This virus was designed to overwrote the BIOS chips on PCs.
Our recommendations
The following practices will enhance the protection you get from your antivirus software.
