In addition to installing antivirus software that automatically updates, consider these software downloads (many of which are free) to thwart third parties from tracking your activities on the Web, says L. Jean Camp, an expert on online risk and the director of the security informatics program at Indiana University, in Bloomington.

Ad-Aware: Removes malicious spyware on your computer. Free for home computer use with limited features. lavasoft.com

ZoneAlarm: This firewall watches for suspicious network activity. zonealarm.com

Firefox: This free browser is considered to offer a higher level of security than Internet Explorer. mozilla.com/firefox

Download these Firefox add-on applications for more security:

Adblock Plus: Removes banner ads, which can be malicious. adblockplus.org

BetterPrivacy: Removes Flash cookies, which track your movements on the Web and store lots of information about where you go. addons.mozilla.org