COMODO Internet Security Pro 4 combines an antivirus engine, powerful firewall, behaviour-based malware blocker and sandboxing module to keep malware firmly locked out of your PC.

The antivirus protection worked much as we’d expect: there’s real-time scanning of the files you access, Explorer integration provides a right-click option to scan the files or folders you specify, and of course you can schedule unattended scans to run whenever you like. Its virus definitions are only updated daily, though – other suites upgrade hourly, or even more frequently.

There’s better news with the suite’s Defense+ module. This monitors the activities of every executable file that it doesn’t recognise as safe, and automatically alerts you to suspicious behaviour like attempts to change system files or key Registry settings.

Defense+ used to be very noisy, displaying pop-up alerts on regular basis, even for entirely innocent programs, but COMODO have worked on the problem and this version shows major improvement. In our tests we had just a single false alarm, while the program correctly detected every attempt to compromise the system.

Another new feature in this version is sandboxing, a technology that isolates applications from system files and Registry settings. This ensures that even if malware manages to launch itself on your PC, it’s limited in what it can do.

The sandbox is a welcome addition, but right now at least there’s a chance that it can interfere with legitimate applications. When we launched an old copy of Paint Shop Pro, for example, the program displayed an error message complaining that it “couldn’t change the System Registry”. Fortunately it’s easy to tell Internet Security Pro 4 not to run a particular app in the sandbox, and Paint Shop Pro immediately returned to normal.

Elsewhere, an excellent firewall provides real online protection. This does a good job of detecting and setting up your network connections during installation, ensuring local PCs aren’t blocked from accessing your network resources. It uses a huge database of trusted apps, which means you won’t have to endure endless pop-ups asking if it’s safe for “firefox.exe” or “outlook.exe” to go online. And it then provides a handy traffic meter for the Internet Security Pro 4 summary page, so for instance as we write it’s explaining that Skype.exe is responsible for 93.0% of internet traffic on our test PC, 6.8% is due to Outlook, and 0.2% is driven by svchost.exe. This simple scheme alone will alert you to unusual traffic patterns that could indicate a malware infection.

And COMODO Internet Security Pro 4 is rounded off nicely with a couple of bonus extra features.

TrustConnect is a service that will encrypt and secure your wi-fi traffic, so preventing eavesdroppers at wireless hotspots from stealing your personal information.

And, perhaps most valuable of all, if you’ve a problem setting up the program, resolving a network issue or removing malware, then you can launch a chat tool and talk immediately to a live support person who will give you personalised, expert assistance. So there’s no sending emails, then waiting days for a reply here – when we tried the feature, “Andrew1” replied to us and was ready to help within seconds.