Help prevent computer 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:

Use an Internet firewall.Note: Windows Vista and Windows XP with SP2 has a firewall already built-in and turned on by default.
Visit Microsoft Update to verify your settings and check for updates.Note: If you've installed the most recent version of Microsoft Office, Microsoft Update will also update your Office programs. If you have an earlier version of Office, use Office Update.
Subscribe to antivirus software and keep it current.

Never open an e-mail attachment from someone you don't know.
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.
Use a standard user account unless you need to use an Administrator Account. For more information, see Why use a standard user account instead of an administrator account.
What about spyware?

Although spyware programs are different from viruses, some can behave like viruses and pose similar and other risks. To help protect against spyware, use antispyware software such as Windows Defender. Windows Defender comes with Windows Vista. If you use Windows XP SP2, you can download Windows Defender for no charge.