Odds are good that when you buy a new computer, it will come loaded with an anti-malware program. Acer and Dell, for example, include a free McAfee trial with their laptops, and Toshiba includes a Norton free trial. But there’s no need to pay when the trial runs out: You can get good protection, especially against online threats, free of charge.
Our evaluations, performed in conjunction with International Consumer Research & Testing, an association of independent, nonprofit organizations, turned up free programs that should adequately protect all but the most at-risk Internet users from malware—viruses, spyware, and other online threats.
Pair a free program such as Avira, which we recommend, with other free tools to build a “suite” that should keep you safe. Make sure Windows’ firewall is on, to help prevent malware from downloading and keep malicious websites from grabbing data off your computer. But if you remotely access files on your computer when you’re away from home, for example, you will need stronger protection.
Windows also includes limited parental controls that let you block specific games or programs and place time limits on computer use. For more-robust controls, such as protection when your child is browsing, consider a full software suite.
If your e-mail program often allows spam messages into your inbox, add a free anti-spam program such as Spamfighter. Browsers such as Firefox warn if you’re visiting a risky site.
Apple computers experience far fewer attacks than PCs. Apple’s firewall and other security features offer sufficient protection. But Mac users may want to install an anti-malware program to avoid passing on Windows malware to others.
Before you install free software, uninstall any pre-loaded security programs. Some free programs might have persistent pop-ups that try to sell you the pay version, though that was a minor annoyance with the recommended Avira.
Pay suites offer more features and are simpler to use, with a single interface, just one download and installation, and a single upgrade from time to time.
Watch for automatic renewals once your subscription ends, especially if you’re not planning to use the program again. Anti-malware programs let you know when your subscription is about to end with pop-up messages. Several automatically renew, although you can opt out of that service.
Editor's Note: A version of this article appeared in the June 2012 issue of Consumer Reports magazine with the headline "Security Software."