In its more malicious forms, it can disrupt the PC so much that it is unusable; it can run up modem bills, it can spam or send copies of itself to everyone in your address book and it can download pornographic material to your PC.

The last is probably the one most likely to make everyone stand up and take notice. Downloading porn at the office can get you fired, downloading child porn anywhere can get you arrested.

The only way to keep these and all the other problems associated with spyware from infecting your life and disrupting your activities is prevention. As the old saying goes, an ounce of prevention is worth a pound of cure.

There are numerous programs available (both for free and for pay) that offer protection from spyware and its related cohorts. Most free programs remove spyware that's already been downloaded and installed to your machine, such as Ad-Aware, one of the first original anti-spyware programs.

The free version requires that you scan to capture and remove spyware. The pay for version includes a real-time scanner that actually prevents spyware from downloading or installing itself.

There are numerous other products on the market, but don't be taken in by their pronouncements of being anti-spyware. Be wary, a few of the free programs are just spyware themselves.

Security for your PC at the home includes using up-to-date virus software, installing an effective firewall, employing reputable anti-spyware tools, making sure all patches and being sure to install all updates for the operating system. The best thing to do is to avoid risky online behavior or the downloading of every free offer that literally "pops up".

Never download anything from an unknown source. A lot of home PC users can find their machines besieged by problems because they downloaded something they weren't sure about or just assumed was safe. Don't assume, be sure. You can even check security settings for different websites you visit. Be sure what you're downloading is from a reputable source.

You wouldn't invite just anyone who knocked on your door into your house; you shouldn't let any file or program into your computer. Spyware at its best is a nuisance, and a potentially dangerous and damaging element that can cost you real time, and worse of all, money.