To protect against emerging viruses, antivirus software with the latest virus-scanning engine should be installed.
  Day by day, new viruses are detected one after another, even though some of them may look exactly the same as existing viruses, they are in fact subspaces of a specific virus. So the antivirus software should be kept updated so it can properly deal with such new viruses.
  Some new computers have trial-antivirus-software pre-installed. Note, however, that after a specified period of time, those programs cannot be used or their definition files cannot be updated.

  Computer viruses are often contained in email attachments. Even if the email is from your close friend, scan the attached files for viruses before opening them.

  Various files such as image files, music files and video files can be downloaded from the Internet, but there is a possibility of a malicious program or instruction code being embedded in those files. To avoid this, be sure to scan downloaded files before using them.
  Also, when downloading files, be sure that the Web site is secure. You should not download any files from suspicious Web sites, including sites where URLs are advertised in SPAM mails.

  When using mailer software to send or receive emails, or a web browser to access Web sites on the Internet, utilize the security functions/ settings supplied with the application software.
  As a mean to protect your computer from Spyware, it is also recommended to set the privacy level to “Medium - High” or higher.

  Recent viruses exploit vulnerabilities (or security holes) in the operating systems and application software. If there is any vulnerability, your computer can be infected with viruses only by previewing emails or accessing the Internet.
  For example, vulnerability in mailer software allowing the automatic execution of attachment files can be exploited by viruses, which can cause a broader damage. Such vulnerabilities are detected at short intervals, so it is important to periodically visit the vender's Web site and check for any related information on the application (in particular, mailer software and browsers) you are using, and then apply the latest security patch available.

  If you have encountered symptoms listed below, you computer may have been infected with computer viruses. Do not overlook them and scan your computer for viruses.

1. System or application software often gets hosed (freezes), or the system does not start.
2. Files disappear. Unknown files exist.
3. Strange icons appear on the task bar.
4. Attempts are made to access the Internet without any operation.
5. Emails are sent without the user’s consent.
6. Can intuitively sense that there is something wrong with the computer.

  Data corrupted by viruses cannot be restored by using antivirus software. Make it a rule to back up data on a regular basis so you can restore the system from any damage caused by virus infection. In addition, keep in a safe place the original CD-ROMs of application software. Should the contents of the hard drive be damaged, you can restore them using the CD-ROMs.