They are products dedicated to remove or block spyware. Lavasoft's Ad-Aware SE, Steve Gibson's OptOut, Patrick Kolla's Spybot - Search & Destroy , Windows AntiSpyware etc are examples of anti spyware. Symantec, McAfee and Sophos have added anti-spyware features to their existing anti-virus products. Some antiviruses categorizes spyware programs as "extended threats" and treats them.
Anti-spyware programs can block spyware in two ways:
1)Anti-spyware software programs can be used solely for detection and removal of spyware software that has already been installed onto your computer. scans of your computer can can be scheduled to weekly, daily, or monthly to scan windows registry, operating system files, and installed programs on your computer. a list of any threats found will be displayed to the user and prompt him for action. This is the popular method. Thus they remove files and entries which match a list of known spyware components
2)They can provide real time protection against the installation of spyware software on your computer.The anti-spyware software scans all incoming network data for spyware software and blocks them . it may also intercept attempts to install start-up items or to modify browser settings.
a frequently-updated database of threats is required by the antispyware software. anti-spyware developers discover and evaluate the new spyware, making "signatures" or "definitions" which allow the software to detect and remove the spyware . Some programs rely partly on historical observation.
Rogue anti-spyware programs
Malicious programmers have released a large number of fake anti-spyware programs, and widely distributed Web banner ads directing them to purchase programs which do not actually remove spyware but in the place may add more spyware of their own.
For more visit this link: