Windows Firewall should suffice for most people. It sits quietly in the background until it detects a suspicious connection attempt, and it's as low-maintenance as low-maintenance can be--but it can detect only inbound penetration attempts.
ZoneAlarm Free Firewall monitors both inbound and outbound traffic for suspect behavior. Weird outbound connections could be signs of an infection, so monitoring in that direction can be valuable. Training ZoneAlarm takes quite a bit of manual labor, though, and the program has a bad habit of installing a toolbar and changing your browser's homepage and search provider unless you're careful during installation. Aside from that, though, it works as advertised and is easy to use.
Beef up your browser
With the two mainstays of PC security in place, it's time to turn to the more granular stuff.
The Internet is rife with infected or downright malicious websites. The big three browsers do a good job of warning you when a site is known for peddling malware, but they aren't so deft at identifying phishing scams (for example). The free Web of Trust and McAfee SiteAdvisor browser plug-ins crowdsource information to let you know when a site could be dangerous, using easy-to-interpret green, yellow, and red icons to indicate the page's threat level.
If you're deeply worried about Web threats, consider installing Google's Chrome, which beat all comers in security in PCWorld's battery of browser tests, thanks to a sandboxing feature that quarantines each tab to keep potential malware from spreading. You can also check out our tips for locking down Chrome even more--as well as our Firefox and Internet Explorer security tips, if Google doesn't float your boat.
Keep your software updated, silly!
Secunia Personal Software Inspector--a program that keeps all of your installed software up-to-date--isn't explicitly security software, but it's one of the most important pieces of the safety puzzle for any patched-together security system. Old, outdated software is often riddled with vulnerabilities that canny crooks can use to gain access to your PC. Secunia PSI ensures that all your system's known weak points have been reinforced with the most recent fixes from the software's developers. Seriously: Get this now.
Use a password manager
Considering how often big-name websites succumb to hack attacks, strong password management is a must. Reusing passwords is just begging for disaster! And though it's possible to create strong, memorable passwords by using mnemonic tricks, everyday users will probably find it easier to depend on a password manager to take the headaches out of online security.
I prefer KeePass, a free, open-source password manager that works across a wide array of devices and packs a random password generator. Some of my cohorts love LastPass and Dashlane. All are great--pick one and use it.
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