"We had an outside lab create some variations of known viruses, which we keep on a disc in a safe here in the lab. We ran them on a virtual machine, which is a virtual computer which is completely physically and electrically separated from any other computer or network," said Dean Gallea from Consumer Reports.
Those viruses were used to test the software to see if it would detect them.
Certain programs use a pig squeal to alert you.
"To test the anti-spam programs, we ran a 'bad e-mail' test to see how well the programs could detect real spam that we collected and a 'good e-mail' test to see how often the software actually removes e-mail you wanted to keep," said Gallea.
McAfee and BitDefender both came out on top in Consumer Reports' tests. They sell for $50.00 for a year of protection.
"If you just need basic protection and you can be sure that everybody practices careful computing at home, then freeware can be a good option," said Gallea.
Consumer Reports also tested three free programs that you can download: Avira's antivirus software, Microsoft Windows Defender anti-badware program, and SPAMfighter's anti-spam software. All are easy to use.
One way to protect your computer is to turn it off when you aren't using it for long periods, or at least disconnect it from the Internet. That reduces the chance that a malicious computer can access your operating system.