Millions of computers in this country are tied into a zombie network. That is, they've been hijacked by a hacker who can remotely control that machine.

You fight off these hackers with good security software and by making sure your fire wall is turned on. Then what?

"Don't be stupid!" says Dan Tynan, a contributing editor at PC World Magazine. He says most malicious software is still spread the old-fashioned way - through attachments in e-mail.

Peer-to-peer file-sharing networks are another easy way to get infected.

"And now it's being spread through things like MySpace, if you click on the wrong video on MySpace," Tynan says. "You run any sort of media file and you run the risk of being infected. So the idea is be very careful out there."

You'd think that if your computer was tied into a zombie network, you'd know it, but Tynan says, you may not.

"The signs that someone else is using your computer - like the hard disc light is flashing and you're not using it or its suddenly sluggish - most of those signs could also be signs of something else. There's nothing that's really definitive. So for the most part if you have zombie at home, you'll never know it."

For More Information:

Read Dan's most recent article: "15 Tech Myths: Busted and Confirmed"