A Consumer Reports survey found consumers paid as much as $7.8 billion over two years to replace computers that got infected with viruses and spyware.
"There is a very high national cost to this," said Jeff Fox, technology editor of the consumer magazine. "People think they're invincible, even when this kind of money is involved."
In a nationwide survey, the magazine found that unwanted commercial e-mail, known as spam, is the biggest computer-security problem. But viruses are the most expensive, with people paying $5.2 billion in 2004 and 2005 to repair or replace afflicted machines, the survey found.