What do Viruses do?
How can I avoid becoming infected?
What is a virus scanner?
How often should I update?
How do I check to see if I already have a virus?
What about updating other software?
Should I worry about attachments?
What do I do if I receive a suspicious e-mail?
What do I do if the virus scanner shows an infection?
What if I think I'm infected and I don't have a virus scanner?

Viruses can have a range of effects. Some are relatively harmless and may just pop up a political slogan or humorous greeting on your PC. Others are much more aggressive and can delete or steal your precious data or stop your programs from working correctly.

Unless you never use the internet and never load new programs or data onto your computer, it is impossible to guarantee that you will never get a virus infection. However, there are several things you can do to minimize the risk.

• Always use a virus scanner
• Keep it up to date
• Be wary of unsolicited attachments
• Always back up your data

A virus scanner is a program that runs in the background on your computer and constantly monitors the system for suspicious actions and checks files for viruses before you open them. There are several to choose from. Two of the best known are Norton Antivirus and McAfee VirusScan. They are not expensive (about $50) and widely available from both retail and mail-order suppliers, as well as being downloadable from the links given here.

Unfortunately, once you have installed a virus scanner, the job is not over. The program as you buy it out of the box will only be good for checking for viruses known about when it was issued (and that could be some time before you actually bought it). Most virus scanners have methods for trying to anticipate future viruses, but the only reliable way to continue protection is to keep the product up to date. Updates are available on-line from both Norton and McAfee. Usually these are free for the first year, but you may have to pay a subscription after this period.

Corporate IT security departments will often update their antivirus software at least weekly. For best protection, the home user should do the same. You should certainly update when there is a reported outbreak of a new virus. Both Norton and McAfee can be configured to update automatically.

Remember also to do a full scan of your system periodically to ensure that you are free of viruses. Remember to set the scan to look at as many file types as possible, including compressed files. It's better to take slightly longer than to miss an infection. You can customize the scanner for whether it cleans the virus automatically or waits for a prompt from you.

Even if you have an up to date virus scanner, regard it as the last line of defense, not the first. There are a few simple rules that will help you minimize your chances of becoming infected

As well as keeping your virus scanner up to date, you should also make sure that your web browser and e-mail program are up to date. The most common programs, Internet Explorer for web browsing, and Outlook or Outlook Express for e-mail, are designed to be as easy to use and as widely compatible as possible. Frequently this means that they are not secure, and these security weaknesses are exploited by virus writers. Check the Microsoft Windows Update site for the latest patches and updates. For instructions on running Windows update, click here.

Always be very suspicious of attachments, as these are the usual means of spreading viruses. Some file types are more likely to carry viruses that others, but even a simple Word document can have a destructive payload. Many companies have a policy of never opening any attachments. It is up to you whether you want to go this far, but you should certainly be wary of unsolicited attachments, even if it is from somebody you know, as viruses use address books to spread. If in doubt, contact the sender to confirm that it is genuine before opening it.

Fortunately, many virus authors seem to lack imagination when composing their messages, and you should be exceptionally suspicious of invitations to view or comment on a document or promises of titillating pictures.

If you are at all suspicious about a note, don't open it. Delete it without opening, and then delete it from the "deleted mail" folder as well. If you do both of these, you should be safe. Remember, it's better to delete a safe note than open a virus - the author can always send it again if it was genuine.

Follow the instructions given by the program for removing the infection.

Go out and buy one. While prevention is better than cure, you can use the virus scanner to clean up a preinfected system. You can also remove the virus manually in many cases. Both Norton and McAfee have detailed instructions on how to remove most viruses