Microsoft this week quietly released a second major version of its free security solution for individuals and very small businesses, Microsoft Security Essentials (MSE) 2.0. This version of the product looks and works much like its predecessor, but unlike the original version, which appeared in September 2009, the new version offers deeper integration with other Windows-based security technologies, including Windows Firewall and the web-based attacks protection in Internet Explorer. Like its predecessor, MSE 2 is free and works with Windows XP, Vista, and 7.

As a refresher, MSE 1.x was codenamed "Morro" and succeeded the subscription-based Windows Live OneCare. It fills in the gaping security hole in modern Windows versions by adding anti-malware functionality, providing protection against viruses, worms, spyware, and other electronic attacks. MSE has always provided a super-simple user interface, and most people won't even notice it's installed, since the UI doesn't annoy with pop-ups and other useless notifications like its predecessor. I use and recommend MSE on all of my PCs, including those used by my wife and children, none of whom are technically sophisticated. It's served us well, and none of our PCs has ever been successfully attacked.

With MSE 2, Microsoft is evolving this product in a few meaningful ways. Setup is as simple as ever, and while the main MSE application window is now curiously busier looking thanks to an unnecessary web-like graphical background, it retains the same basic UI of its predecessor, with the same Home, Update, History, and Settings tabs.

New features include:

Windows Firewall integration. MSE 2 integrates with the built-in Windows Firewall and will prompt you to enable this integration during Setup. This way, MSE can include firewall monitoring as part of its overall PC health monitoring.

New protection engine. The MSE antimalware engine has been updated to offer enhanced detection and cleanup capabilities with better performance.

Network inspection system. MSE 2 now helps protect against network-based exploits.

Other improvements. MSE 2 includes other important, if hard-to-find, changes. You can specify that CPU usage not exceed a certain limit (the default is 50 percent) during scheduled scans. MSE 2 reports when definitions were checked in addition to when they were updated so that you can be sure it's working properly if a long time has elapsed between definition updates. The real-time protection functionality offers more fine-grained control. You can now auto-remove quarantined files after a specified interval, though that option is disabled by default. And Microsoft now allows you to opt out of Microsoft SpyNet, the online community that ensures that MSE stays up to date; I don't recommend doing this for obvious reasons.

One feature, enhanced protection from web-based threats, was removed very late in the beta. According to Microsoft, this feature was removed for performance reasons.

I've updated my primary PC and laptop with MSE 2 and will continue to evaluate this version to see whether I can recommend it as strongly as its predecessor. I'm guessing that will certainly be the case, based on my excellent experiences with the beta version. If you're undaunted by new software, head on over to the Microsoft web site--MSE 2 is not yet available via the main MSE web site--and download the new version.