You have until 3:00 am EDT 9:00 am EDT Wednesday morning, August 13, to download ZoneAlarm's ForceField browser virtualization envelope and receive a license key good for a one-year subscription to the product on one PC.

The basic premise of ForceField is to build a kind of virtualization envelope around the active Web browser, where essentially anything to which a browser would normally connect is divided from the operating system by one layer of abstraction. When a malicious tool tries to leverage a security hole in some other product by way of communicating with the browser -- as was the case with last year's exploit of Apple QuickTime, which relied on Mozilla Firefox -- it won't find that hole because it doesn't appear to exist within the abstraction layer.

"ZoneAlarm ForceField diverts all automatic reading and writing attempts as you surf the Web," writes parent company CheckPoint Systems general manager Laura Yecies in a blog post today, "to an emulated, or 'pretend' part of the operating system, isolating your 'real' operating system from automatic drive-by-downloads and Web-based malware. It's essentially a reverse-trick."

As it turns out, ZoneAlarm wasn't the first to try this idea. In the fall of 2006, a company called GreenBorder unveiled what was believed at the time to be the first browser-specific virtualization envelope -- in that case, for Firefox. But Google acquired the entire project in May 2007, and has since done nothing with it. At last check, the former company's Web site was on automatic pilot, taking customer support messages from users of its prior products. CheckPoint later unveiled ForceField in September 2007.

ForceField is also a component of the most recent beta of ZoneAlarm Extreme Security, which also includes the original ZoneAlarm firewall and CheckPoint's consumer-grade anti-virus product. Fair warning: Not all of our FileForum reviewers found ForceField particularly impressive.

As reviewer darthbeads wrote last June, "This coding disaster that is ForceField is beyond awful. All of the browsers on my system (IE7, Masthon, Firefox, Opera) literally drag to a crawl that would make a drunk, one-legged, obese turtle look downright meteoric."

It may be supreme protection for your browser, or it may resemble an inebriated, quadriplegic reptile. For free -- at least for the first year -- it may be worth finding out for yourself.