ZoneAlarm Free Antivirus + Firewall is a straightforward security tool which takes ZoneAlarm's powerful firewall and Kaspersky Lab's antivirus engine and bundles them into a single package.
Installation is quick and easy (though beware, it'll install the ZoneAlarm browser toolbar unless you choose the Custom Install option and decide otherwise). And the package does its best to avoid conflicts with other antivirus packages. So if you have one installed already then ZoneAlarm Free Antivirus + Firewall will detect this and turn off its real-time protection to avoid clashes.
Otherwise, though, there are plenty of scanning options: you get multiple scan modes (Quick, Full, Full with Archive files), a versatile scheduler, and a vast array of settings to tweak (there are 22 "Behavioural Scan Options" alone).
As you'd expect with a ZoneAlarm product, you get a solid firewall which blocks incoming attacks, makes sure only approved applications can get online, and again offers plenty of low-level manual controls should you need them.
And as a bonus there's also basic phishing and identity protection, with 5GB of online backup space thrown in for good measure.
As you can see, there's no shortage of functionality here, but unsurprisingly the commercial versions do have some notable improvements. Opting for ZoneAlarm's Internet Security Suite ($39.95) gets you everything in the free build, plus more frequent antivirus updates (hourly vs only daily for the free edition), parental controls and technical support available 24/7. And the Extreme Security edition ($44.95) adds sandboxed browsing and a PC Tune-up module to enhance your PC's performance. Find out more on the ZoneAlarm website.