What is a VIRUS and ANTIVIRUS

Antivirus software are programs which can detect, prevent and clean up computer viruses which may attempt to infect your computer system. It will scan downloaded files as well as your entire computer system in order to detect the presense of an infection. Before getting into anymore information about antivirus programs let's first learn some basic information about computer viruses in general.

A computer virus is much like the human verison in that it's purpose is to spread from system to system, replicating itself all the while causing damage to each infected host. A computer virus can range in size and purpose but typically they are small bits of code which are hidden in or attached to other files. The word virus is often a broad term which is used to refer to things such as worms, spyware, adware, malware, trojan horses and rogue software but all these things are actually different and fall into a class of there own. The problems and damage that are caused by an infecton can be extremely varied. The infection may be as simple as a prank that will cause strange noises, pop-ups and other annoying instances to occur on your system. They may delete files and slow down your system or they could even damage your hardware or posibly destroy your entire computer system. Once on your system an infection will spread by attaching to other programs and files within your system. Viruses will often not just replicate within your system but also attempt to spread to other systems outside of the locally infected one by methods such as taking control of your email and sending out copies of itself to those in your contacts list.

There are several ways that your system may become infected. The most common way a virus is spread is thru infected attachments to email. These attachements may come in the form of pictures, videos, sound clips or just about any other type of file that can be attached to an email. Infections can also be spread through internet downloads. These could be completely legimate files or links which have been altered unknowingly to include a virus or they can come from illegal software downloaded via peer-to-peer programs or other services.


Here are some signs that may indicate that your system may have been infected.
The occurance of random pop-ups, noises or music.
Random files and icons appearing on your desktop or other places when you did not install such things.
Files and icons which were on your system before have disappeared without you having uninstalled or moved them.
A high number of unusal error messages occuring.
On screen text, graphics, pop-ups and dialogs become distorted or unreadable.
Hard disks, cd/dvd-drives or other hardware components can no longer be accessed.
Applications are no longer accessible with passwords when you have not changed the password.
Programs which worked properly before run slowly or do not run at all.
Your system becomes exremely slow or constantly freezes.
Your system crashes and reboots every few minutes or simply will no longer boot at all.

These are just some of the signs that your system may have been infected and every infection will cause different sets of problems or problems which may not be listed here.



Virus Prevention

The best way to stop a computer infection is to prevent it as this is a much less tedious task then attempting to clean up your system after it has already been infected. There are a number of steps that you can take to esure the security and prevent an infection of your system. These steps include never downloading email attachments from email accounts that you do not know. Never downloading email attachments from known email accounts that seem out of the ordinary or suspicious. Downloading files from trusted and reputable websites and other reputable sources and when at all possible using checksums to ensure a files integrity. Checksums are a form of encryption that can help show if a file has been altered from its original state and most reputable companies will post a checksum to ensure a downloaded file has not been changed or the downloaded file is the correct file. Make sure that you have good firewall in place on your network. Make sure that your system always has the most recent updates installed. You can do this in Windows 7/Vista by using the Windows Update feature. Next you will want to click Check for Updates to look for the latest updates and install them if there are any. On Windows XP you will want to run the sysdm.cpl command. Next you will want to click Automatic Updates tab and finally click the ok button. Most importantly make sure that you have a trusted antivirus program installed on your system and that it is up to date and that it is active. There are a number of good antivirus programs to choose from including Norton AntiVirus, AVG AntiVirus and McAfee AntiVirus. Which one you use may simply come down to personal preference.
Recommended Antivirus Software

While you can download free software, we have found that the paid versions of antivirus suites are usually more robust and could possibly provide better PC protection. 

AVG AntiVirus

BitDefender AntiVirus
F-Secure AntiVirus
Kaspersky AntiVirus
McAfee AntiVirus
Panda AntiVirus
PC Tools Internet Security
Symantec Norton Antivirus & Norton 360
Trend Micro Internet Security
Webroot AntiVirus

Free Antivirus Software 

PC Tools AntiVirus Free EditionAVG AntiVirus Free Edition
Microsoft Security Essentials
Panda Cloud AntiVirus
PC Tools AntiVirus Free Edition