What is a virus?

A computer program that can reproduce by changing other programs to include a copy of itself. It is a parasite program, needing another program to survive.

Virus cause an unexpected usually negative event without user knowledge or permission. It can damage your software, hardware, and your files.

Most viruses do not spread without human action to move them along, such as sharing a file or sending an e-mail.

What is a worm?

A worm is a special type of virus that reside in the active memory of a computer and replicate itself. Once you have a worm in your system it can travel alone. Worm replicates itself in great volume.

A worm could send out copies of itself to everyone listed in your e-mail address book, and their computers would then do the same. This will cause a heavy network traffic that would slow down business networks and the Internet as a whole. Because worms exist as separate entities, they can tunnel into your system and allow somebody else to take control of your computer remotely.

What is a Trojan Horse?

Trojan Horses are impostors--files that claim to be something desirable but, in fact, are malicious. A very important distinction between Trojan horse programs and true viruses is that they do not replicate themselves.

Trojan Horses deliver a harmful effect such as opening up a security hole, spreading itself via email, or deleting or damaging files. Trojan Horses spread when people open a program because they think it comes from a legitimate source. It can also be included in software that you download.

How do worms and other viruses spread?

Viruses and most worms can only spread if you open or run an infected program.

Many of the most dangerous viruses were primarily spread through e-mail attachments-the files that are sent along with an e-mail message. The virus is launched when you open the file attachment. If you receive an e-mail with an attachment from someone you don't know you should delete it immediately. Unfortunately, you're no longer safe opening attachments from people you do know.

Viruses and worms have the ability to steal the information out of e-mail programs and send themselves to everyone listed in your address book. So, if you get an e-mail from someone with a message you don't understand or a file you weren't expecting, always contact the person and confirm the contents of the attachment before you open it. Other viruses can spread through programs you download from the Internet or from virus-ridden computer disks that you borrow from friends or even buy in a store. These are less common ways to contract a virus. Most people get viruses from opening and running unknown e-mail attachments.

Protect Yourself Against Viruses

Unfortunately, there is no way to guarantee 100% that you will avoid computer viruses. However, it is possible to minimize potential damage.

Here are some tips to protect your computer from viruses, worms and Trojan Horses.

1. Do not open any e-mail attachment from unknown, suspicious or untrustworthy source.
2. Do not open an e-mail attachment from someone you know, unless you know what the attachment is.
3. Update your antivirus software regularly.
4. Update your Microsoft software.
5. Always scan removable storages for viruses.

How can I tell if my computer has a virus ...?

Here are some symptoms of PC infected by viruses:

• There is a double extension on an attachment that the user opened. For example .jpg.vbs
• The computer may slow down, stop responding or crash and restart every few minutes.
• An antivirus program is disabled for no apparent reason.
• An antivirus program will not install on the PC but other programs will.
• Files are missing.
• A program that was used successfully has disappeared, and the user knows that he/she didn't uninstall it.
• The PC starts performing actions seemingly on its own, like moving the mouse pointer, opening or
closing windows, running programs or opening and closing the CD tray.
• Odd icons appear on the desktop that the user didn't place there.