PC users know little about computer security

Fully 87 percent of Americans polled said they had anti- virus software, 73 percent said they had a firewall and 70 percent said they had anti-spyware software, according to the survey by security software maker McAfee and the National Cyber Security Alliance.

But when pollsters asked to remotely scan the respondents' computers, the story turned out to be very different.

While 94 percent of those polled had anti-virus software, just half had updated it in the past month, the survey showed. Eighty one percent had a firewall protecting private information, but just 64 percent had enabled it. And 70 percent said they had anti-spyware software, but only 55 percent had enabled it.

Spyware not only monitors what a computer user does, but can also install software without the user's consent and interfere with the computer in other ways.

Bari Abdul, a McAfee vice president, said most viruses were not written by attention-seeking hackers looking to pull a prank.

"Most of the action has gone to stealing identity," he said after speaking at a cyber security conference sponsored by the National Cyber Security Alliance.

Nine percent of those polled reported having had their identity stolen, he said.