· Keep it turned on.

· Update the software regularly.

· Set it up to scan e-mail attachments.

Programs from some Web sites are risky. It is a good idea to avoid clicking OK or Yes at pop-ups that ask you to install software, unless you understand what the software is and that you trust the source.

· Before you open files attached to e-mail (attachments), scan them first using virus protection software.

· Do not open unknown attachments.

As you use the Web, you can encounter software—often invisible to you—that can cause problems with your computer. Examples of such problems can include the following:

• Changing your Web search results to advertisements instead of your search results

• Slower system speed from your computer

• Interference with other software

This can result from malicious software (also known as malware) that is installed on your computer without your knowledge. Malware can include advertising software (adware) that displays ad banners on screen, and spying software (spyware) that gathers information about your Internet activity.

Adware and spyware are annoying, both in the problems they can cause and in the steps you can take to manage the problem. Here is what you can do:

• Install and regularly use ad- and spyware blocking software. You can often find such software free of charge on the manufacturers' Web sites, as well as reliable software distribution sites. You can also check with software retailers.

• Update the software regularly.