The excitement home buyers feel when taking a new PC out of its box can be short-lived if the machine is vulnerable to the swarm of viruses and worms on the Internet.

Current PC users are constantly reminded about the need to download patches and operating system updates as soon as they are made available. But those users may not realize that a "new" PC might actually have been sitting in a warehouse for several months, and might lack the most recent patches required to keep it safe from viruses and worms.

Read more: PC World.