What is a computer virus?

What is a computer virus?
Computer viruses are software programs deliberately designed to interfere with computer operation, record, corrupt, or delete data, or spread themselves to other computers and throughout the Internet, often slowing things down and causing other problems in the process.

Just as human viruses range in severity from the 24-hour flu to the Ebola virus, computer viruses range from the mildly annoying to the downright destructive, and come in new and different forms. The good news is that with an ounce of prevention and a little knowledge, you are less likely to fall victim to viruses and you can diminish their impact.

How do viruses work?
Basic viruses typically require unwary computer users to inadvertently share or send them. Some viruses that are more sophisticated, such as worms, can replicate and send themselves automatically to other computers by controlling other software programs, such as an e-mail sharing application. Certain viruses, called Trojans (named after the fabled Trojan horse), can falsely appear as a beneficial program to coax users into downloading them. Some Trojans can even provide expected results while quietly damaging your system or other networked computers at the same time.

Although it's good to be aware of these different types of viruses and how they work, what is most important is that you keep your computer current with the latest updates and antivirus tools, stay current about recent threats, and that you follow a few basic rules when surfing the Internet, downloading files, and opening attachments. Once a virus is on your computer, its type or the method it used to get there is not as critical as removing it and preventing further infection.

Nothing can guarantee the security of your computer 100 percent. However, you can continue to improve your computer's security and decrease the possibility of infection by keeping your system up-to-date, maintaining a current antivirus software subscription, and following a few best practices.

Steps to help avoid viruses:
1. Visit Microsoft Update and turn on Automatic Updates.

Note: If you've installed Office 2003 or Office XP, Automatic Updates will also update your Office programs. If you have an earlier version of Office, use Office Update.

2. Use an Internet firewall (Note: Windows XP with SP2 has a firewall already built-in and active).

3. Subscribe to industry standard antivirus software and keep it current.

4. Never open an e-mail attachment from someone you don't know.

5. Avoid opening an e-mail attachment from someone you know, unless you know exactly what the attachment is. The sender may be unaware that it contains a virus.

How do I know if a virus has infected my computer?
After you open and run an infected program or attachment on your computer, you might not realize that you've introduced a virus until you notice something isn't quite right.

Here are a few primary indicators that your system might be infected:
• Runs consistently slower than normal

• Stops responding or locks up often

• Crashes and restarts every few minutes

• Restarts on its own and then fails to run normally

• Applications don't work properly

• Disks or disk drives are inaccessible

• Printing doesn't work correctly

• You see unusual error messages

• You see distorted menus and dialog boxes

These are common signs of infection—but they could also indicate hardware or software problems that have nothing to do with a virus. The bottom line is that unless you install industry standard, up-to-date antivirus software on your computer, there is no way to be certain if your computer is infected with a virus or not.