Spyware is a real and prevalent threat to Internet users. These programs may spawn pop-up ads, eavesdrop on you for parties unknown, and/or interfere with your computer's normal functioning to the point of making it unusable. They may install without your knowledge, or you may give them permission to install without knowing the full story on what they do.
Anti-spyware programs try to block spyware before it is installed and/or remove it after the fact. We recommend that you install at least one such program (two or more may be necessary to clean up an infested computer).
Several reputable anti-spyware programs are available free to individual users: