6. Steps to avoid viruses Nothing can guarantee the security of your computer 100 percent. You can continue to improve your computer's security and decrease the possibility of infection by using a firewall, keeping your system up-to-date, maintaining a current antivirus software subscription, and following a few best practices. Tip: Because no security method is guaranteed, it's important to back up critical files on a regular basis before you encounter a virus or other problems. Steps to help avoid viruses: 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. 5. Never open an e-mail attachment from someone you don't know. 4. Subscribe to industry standard antivirus software, such as Windows Live OneCare and keep it current. 3. Visit Microsoft Update and turn on automatic updating. 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 turned on by default). 1.