Antivirus

Make sure you are getting the latest virus definitions (information about the latest viruses) daily with your configuration. This is important, as new viruses are released daily. You will want to schedule a monthly full system scan when you are configuring it. Most anti-virus software does this automatically for you, but it is good practice to verify this.

Windows

AntiVir is free for private, non-commercial use.

AVG Free Edition is free anti-virus software for private, non-commercial, single home computers. It is believed the free version will no longer be free as of January 15th, 2007.