This article is from the Computer Virus for New Users FAQ, by Nick email@example.com with numerous contributions by others.
1. Install anti-virus software from a well-known, reputable company,
UPDATE it regularly, and USE it regularly.
New viruses come out every single day; an a-v program that hasn't been
updated for several months will not provide much protection against current
2. In addition to scanning for viruses on a regular basis, install an 'on
access' scanner (included in most good a-v software packages) and configure
it to start automatically each time you boot your system. This will protect
your system by checking for viruses each time your computer accesses an
3. Virus scan any new programs or other files that may contain executable
code before you run or open them, no matter where they come from. There
have been cases of commercially distributed floppy disks and CD-ROMs
spreading virus infections.
4. Anti-virus programs aren't very good at detecting Trojan horse
programs, so be extremely careful about opening binary files and Word/Excel
documents from unknown or 'dubious' sources. This includes posts in binary
newsgroups, downloads from web/ftp sites that aren't well-known or don't
have a good reputation, and executable files unexpectedly received as
attachments to E-mail or during an on-line chat session.
5. If your E-mail or news software has the ability to automatically execute
to a message, I strongly recommend that you disable this feature.
6. Be _extremely_ careful about accepting programs or other files during
on-line chat sessions: this seems to be one of the more common means that
people wind up with virus or Trojan horse problems. And if any other family
members (especially younger ones) use the computer, make sure they know not
to accept any files while using chat.
7. Do regular backups. Some viruses and Trojan horse programs will erase or
corrupt files on your hard drive, and a recent backup may be the only way to
recover your data.
Ideally, you should back up your entire system on a regular basis. If this
isn't practical, at least backup files that you can't afford to lose or that
would be difficult to replace: documents, bookmark files, address books,
important E-mail, etc.