(CIS) provides a sturdy package for blocking viruses, spyware, rootkits, botnets, worms, and other malware.

CIS goes beyond the basic malware protection that you get with a lot of freebies, offering a built-in firewall to guard against hackers and intrusions. Windows comes with a free native firewall, but using CIS's third-party alternative provides more-advanced configuration options. In addition its consistent interface is useful if different versions of Windows run on your network, since the native firewall differs from one Windows version to another.

When in late 2010, we liked how well it blocked new malware, though we found that it had a few drawbacks in other respects. Still, it managed a an overall rating of 3.5 stars--a solid mark.

The program's Defense+ feature analyzes and manages executable files to protect critical system files and to prevent malware from causing harm. It also has automatic sandbox functionality, which runs unknown files in an isolated environment so they can't do any damage if they turn out to contain malware.