PC Tools Threatfire 4.5 is a free behaviour-based antivirus utility that serves as a great supplement to your existing security software, offering superb behaviour-based detection.
Unlike most of the other pieces of free antivirus software that we've tested recently, PC Tools Threatfire is not a stand-alone antivirus program. Instead, PC Tools Threatfire 4.5 supplements your existing security app with highly effective behavioural analysis that can stop malware based solely on what the file tries to do on your PC.
Behavioural detection attempts to thwart the successful hacker tactic of churning out ever greater numbers of malware variants to stay one step ahead of traditional antivirus signature databases (which the majority of security programs use). Other programs employ behavioural or heuristic techniques, too (the latter looks for partial matches with known malware). But behavioural detection like the approach that PC Tools has implemented in PC Tools Threatfire 4.5 can be particularly tricky, as it's prone to accidentally flagging harmless software.
In AV-Test.org's behavioural-detection tests, most apps have only about a 30 percent to 60 percent detection rate. Not so for PC Tools Threatfire 4.5: It warned about every single one of the 15 malware samples used, and it blocked all but one of them. What's more, this nimble malware nabber didn't put up any false-positive warnings. It's hard not to be impressed with such stellar performance.
While running more than one regular antivirus app at the same time can cause major problems, PC Tools Threatfire 4.5 should run smoothly alongside existing security tools. Since it detects only programs that attempt to run, you'll still want a standard antivirus program to perform regular scans and to check files that write to your hard drive, before they get a chance to execute.
PC Tools Threatfire 4.5 is simple to use and defaults to an appropriate medium level of sensitivity, but we suggest turning on the option in Settings, Quarantine to create a system restore point automatically before quarantining anything. As for extras, a nice system-activity monitor provides extensive technical details about all currently running programs, and a mostly just-for-show threat monitor maps global malware outbreaks.
NEXT: our expert verdict >>