There is a good chance someone may be spying on you through your home computer, KMBC's Jere Gish reported.

"I think the spyware's probably the biggest thing," computer security expert Mike Boerschinger said.

Boerschinger said most home computers are filled with software designed to watch the users' movements online and more.

What's in the average family's computer?

"Thirty to 40 viruses, if they're not running virus software, and hundreds of different spyware ranging from the innocuous stuff to the very bad stuff," Boerschinger said.

Spyware could include what is called a Trojan horse, which allows a hacker to take over a machine, or a keystroke logger, which can capture every word that users type.

"I capture keystrokes, I can decipher passwords. I can decipher Social Security numbers if you're doing a lot of financial data, trade secrets, other things just by watching what people type," Boerschinger said.

Unless computer users run software to guard against them, spyware viruses can attach themselves to a computer almost the instant the user goes online.

"Within seven or eight seconds, without having virus software, the machine's infected with a virus," Boerschinger said.

Most computer users run a virus protection program. But it won't guard against spyware. To see just how vulnerable to spyware an unguarded computer can be, Boerschinger and coworkers set up a clean computer and let it sit online unprotected. Without surfing any Web sites, the machine was infected with 14 viruses and three Trojan horse spyware programs.

"The machine is a hacker's paradise. If a machine is sitting out there unprotected, they see it," Boerschinger said.

After downloading just one popular free music file-sharing program, more than 150 spyware programs invaded the computer, Gish reported.

While users should protect their computers from spyware, be careful how it is done. Experts recommend ignoring all the pop-up screens that say your machine has been infected or your clock is not correct. Chances are that those pop-up ads lead to programs that are really spyware in disguise.

Gish reported that most spyware won't be seen. It runs below the surface of any unprotected computer.

"It would be interesting to run software against the person who says, 'Well, that doesn't affect me. My computer's fine.' You would be amazed at what you might find," Boerschinger said.

But there is a simple fix. Boerschinger said downloading a free anti-spyware program will help keep out most of the invaders.

"Are you fully protected 100 percent? Absolutely not. Maybe you're 90 or 95 (percent), but that's better than they typical 35 to 40 percent that the average family has," Boerschinger said.

Gish reported that most spyware just keeps a record of visited Web sites for advertising purposes.

More Information:

Ad-aware

Spybot S&D