Email

• Don't open attachments from people you don't know or attachments that seem suspicious. It is not enough that the mail originated from an address you recognize.
• Disable the Preview Pane view in Outlook and Outlook Express. Some viruses can be launched by simply previewing them, even if the message is never opened. Disabling this feature saves you a lot of grief.

Programs

• Only run programs of known origin
• Enable Macro Virus Protection in all your Microsoft Office programs.

Protection

• Make sure that anti-virus and anti-spyware software is installed on your machine
• Update anti-virus signature. A weekly update is good, although daily is better.
• Remain alert and wary. Anti-virus programs are not fail-safe.
• Disable Java, JavaScript, and ActiveX if possible (comments from CERT)
  How to Disable Active Content in Internet Explorer (notes from Microsoft)
• Use strong passwords for all your accounts

Good Habits

• Only visit trusted web sites
• Make regular backups of critical data
• Turn off your computer or disconnect from the network when not in use
• Educate yourself on the dangers of viruses, spyware, worms, trojans and other malicious software.