Also called adware, spyware is any software that covertly gathers user information through the user's Internet connection without his or her knowledge, usually for advertising purposes. Spyware applications are typically bundled as a hidden component of freeware or shareware programs that can be downloaded from the Internet. Once installed, the spyware monitors user activity on the Internet and transmits that information in the background to someone else. Spyware can also gather information about e-mail addresses and even passwords and credit card numbers.

       Spyware is similar to a Trojan horse in that users unwittingly install the product when they install something else. A common way to become a victim of spyware is to download certain peer-to-peer file swapping products that are available today.

       Aside from the questions of ethics and privacy, spyware steals from the user by using the computer's memory resources and also by eating bandwidth as it sends information back to the spyware's home base via the user's Internet connection. Because spyware is using memory and system resources, the applications running in the background can lead to system crashes or general system instability.

       Because spyware exists as independent executable programs, they have the ability to monitor keystrokes, scan files on the hard drive, snoop other applications, such as chat programs or word processors, install other spyware programs, read cookies, change the default home page on the Web browser, consistently relaying this information back to the spyware author who will either use it for advertising or marketing purposes or sell the information to another party.

       Licensing agreements that accompany software downloads sometimes warn the user that a spyware program will be installed along with the requested software, but the licensing agreements may not always be read completely because the notice of a spyware installation is often masked in obtuse, hard-to-read legal disclaimers.

       Spyware is becoming an increasingly common problem for most PC owners, and if left unchecked can have an almost crippling effect on a system’s performance. There are a few very excellent free tools that I am using and would recomend to everyone.

       The first two are both detection and removal tools. They scan your system for unwanted adware/spyware and eradicate them autimatically or by user interaction.
       Spybot     Click Here
       Ad Aware 6     Click Here
       Once downloaded, install and run the programs in any order, using their built-in update features (use the U.S. update servers for Spybot) to make sure you have the latest possible information for hunting down Spyware before scanning your system for spyware entries. They should both turn up a number of entries, which you can then select and tell the program to “fix,” and they will both do quickly and easily with little or no problem.
       The third program is Spyware Blaster, more of a preventative tool that aims to prevent spyware from getting on to your system. You can download Spyware Blaster from the following:
       Spyware Blaster     Click Here
       Again, once you have it, install, run and update it. Then click the "Check All" Items button followed by the "Protect Against All" Checked Items button and you’re done.