Let’s get one thing clear: PC Tools’ ThreatFire Antivirus Free isn’t supposed to be your system’s primary antivirus solution. This behavior-based virus prevention app is designed to work with your antivirus program, firewall, malware scanners, and other security software, and serve as your first line of defense against zero-day threats. Those are new viruses and other threats making their way around the Internet that security specialists haven’t yet had time to analyze, much less post updates and fixes for them. ThreatFire scans your computer and programs for indicators that something is amiss, taking action when it detects a threat. It can sniff out viruses, adware, spyware, rootkits, and other potential dangers.

ThreatFire must be installed on a clean PC, so the program’s installer scanned our PC to make sure we had no viruses, rootkits, Trojans, or other hidden threats. ThreatFire’s mission is to serve as one of four legs of a comprehensive PC security regime, so the setup wizard also verified that we had an adequate firewall as well as protection from viruses and spyware. Once our system received a clean bill of health, ThreatFire’s interesting interface opened with the Worldwide Detection tab displayed on the main Security Status page, where the program listed the latest detected threats and pinpointed outbreaks on a world map. Clicking Protection Statistics displayed ThreatFire’s log data for our system. ThreatFire offers plenty of options, including exclusion lists, advanced rules settings, default actions, and interface languages.

ThreatFire scanned and verified our system during the installation, but we clicked Start Scan to establish the program’s baseline for our system, choosing the Full Scan instead of the quicker Inteli-Scan option, which targets likely hiding places. The Full Scan is thorough and takes about as long as most virus scans. But most of the time, ThreatFire does its thing quietly, in the background. Since it’s behavior-based, ThreatFire doesn’t require daily updates, but its Smart Update checks for the latest Product, Database, and Language versions. Many antivirus tools now offer behavior-based scans like ThreatFire. If yours doesn’t, or if you want the best tool of its type, ThreatFire Antivirus Free is ready.