What is Anti-virus softwareAnti-virus software is a program that either comes installed on your computer or that you purchase and install yourself. It helps protect your computer against most viruses, worms, Trojan horses, and other unwanted programs that could make your computer or server unavailable and/or destroy your computer data. Viruses, worms, and malicious programs often do such things as delete files, access personal data, and or use your computer to attack other computers.
What are Computer Viruses?A virus is a program or code that replicates itself or copies itself to other programs, computer boot sector or documents. Viruses can be transmitted to your computer as attachments in an e-mail or in a downloaded file, or be present on removable media such as floppy diskettes or CD's. Viruses are usually downloaded by email, files sharing programs, diskettes or CD's you've received without knowing that it contains a virus.
Viruses can infect as soon as their code is executed; other viruses lie dormant until circumstances cause their code to be executed by the computer. Most viruses can be quite harmful, erasing data or causing your hard disk to require reformatting. A virus that replicates itself by re-sending itself as an e-mail attachment or as part of a network message is known as a worm. If your computer gets a virus, which starts spreading to other computers through email or over the network, it may be necessary to shut down your network connection until the virus has been removed from the infected computer resulting in a loss of productivity.
What is Trojan Horse Virus?A Trojan Horse Virus is a program in which malicious or harmful code is contained inside apparently harmless programming or data in such a way that it can get control and do its chosen form of damage, such as corrupting the file allocation table on your hard disk. A Trojan horse may be widely redistributed as part of a computer virus to other networked computers.
What is Worm Virus?A worm is a self-replicating virus that does not alter files but resides in active memory and duplicates itself. Worms use parts of an operating system that are automatic and usually invisible to the user. It is common for worms to be noticed only when their uncontrolled replication consumes system resources, slowing or halting other tasks.
Generally, there are three main classes of viruses:File infectorsSome file infector viruses attach themselves to program files, usually selected .COM or .EXE files. Some can infect any program for which execution is requested, including .SYS, .OVL, .PRG, and .MNU files. When the program is loaded, the virus is loaded as well. Other file infector viruses arrive as wholly-contained programs or scripts sent as an attachment to an e-mail note.
System or boot-record infectorsThese viruses infect executable code found in certain system areas on a disk. They attach to the DOS
boot sector on diskettes or the
Master Boot Record on hard disks. A typical scenario (familiar to the author) is to receive a diskette from an innocent source that contains a boot disk virus. When your operating system is running, files on the diskette can be read without triggering the boot disk virus. However, if you leave the diskette in the drive, and then turn the computer off or reload the operating system, the computer will look first in your A drive, find the diskette with its boot disk virus, load it, and make it temporarily impossible to use your hard disk. (Allow several days for recovery.) This is why you should make sure you have a
bootable floppy.
Macro virusesThese are among the most common viruses, and they tend to do the least damage. Macro viruses infect your Microsoft Word application and typically insert unwanted words or phrases.
How do you get infected?You may be infected if you:1. Insert a floppy disk or CD (or Zip disk or any other removable.) in your computer.
2. Download software.
3. Install software.
4. Receive email.
5. Browse Web sites.
6. Share files or access other another computer.
7. Use any type of network you run the risk of infecting your computers with a virus.
8. Anyone using your pc who has access to the Internet. Computer users can inadvertently download and execute viruses through dowloading, files sharing programs or through personal or business e-mails.
Good PracticesPrevent viruses from infecting your system; install and regularly update your anti-virus software. Most anti-virus software can be set up to automatically scan all processes of your computer and the activity on it. This includes, but is not limited to, the scanning of email (both incoming and outgoing), Web site temp files, downloaded files, removable media such as floppies, CDs, Zip disks, etc., and of course your hard drive.
New viruses are created almost daily, so it is imperative that your anti-virus software be updated regularly to counteract all new viruses. It is recommended to update every week, or more. This is especially true for users of Windows, Microsoft Outlook, Microsoft Outlook Express, the Web, and email.
It is good practice to set up your Anti-virus software to automatically scan you hard disk and network share, nightly, or at minimum twice a week.
It is especially important to run a scan before backing up your hard disks. You certainly would not want to backup a virus!
Are you protected with an online Anti-virus scan?Not at All!An online virus scanner is a tool to demonstrate why you need anti-virus software installed on your system. Because these free scanners do not run continuously on your system, they can only find the infection after the damage has been done.
Free Anti Virus Software LinksAVG Free Edition is still available. Grisoft have been bought out by Intel and a bunch of partners and they are, naturally, pushing the paid-for version. The free version is available at
http://free.grisoft.com/doc/5390/lng/us/tpl/v5#avg-anti-virus-freeAvast 4 home Edition is available from
http://www.avast.com/eng/download-avast-home.htmlAntiVir Personal Edition is available from
http://www.free-av.com/My advice would be to have a look at the three sites named above and check out their support forums.
As with most software it comes down to personal preferences – I use and have been using AVG for 3 years, without any major problems. But the choice is Yours!