A recent McAfee study found that one in every six personal computers have no protection at all -- 17 percent of PCs analyzed either had disabled anti-virus software, or never had any to begin with. The study analyzed data from an average of 27 to 28 million PCs each month whose users ran the free McAfee Security Scan Plus software for Windows computers.

"Web surfers who install Scan Plus are likely to have a problem with their computers that prompted them to use the technology in the first place -- so they might be less well protected than the general population," notes The Register's John Leyden. "McAfee's figures are thus probably best regarded as indicative rather than definitive."

"PCs in Finland, Italy, New Zealand, Germany and Denmark were most likely to be protected, the study found," writes PCWorld's Cameron Scott. "Those in Singapore, Spain, Mexico, Japan, and the United States were least likely to have active antivirus protection."

The country with the worst rating, McAfee said, was Singapore, with 21.75 percent of PCs unprotected. The U.S. also had a surprisingly low rating, with 19.32 percent of consumers using no security software. At the other end of the spectrum was Finland, where only 9.7 percent of PCs are unprotected.

"The freedom to browse the Internet comes with the added risk of unwanted exposure, and cybercriminals are preying on unsuspecting victims," McAfee senior vice president Steve Petracca said in a statement. "With the increasing number of global cyber attacks affecting consumers, it is critical that the 17 percent of consumers that are unprotected update their virus protection before it's too late."