Spybot Search and Destroy is as a free 2.31MB download. The program can be easily installed and it automatically places an icon on your desktop for quick access after installation.

Other Featrues of Spybot Search and Destroy:

Along with spyware and adware detection and disinfection capabilities, Spybot can repair the Registry, Winsock LSPs, ActiveX objects, browser hijackers and BHOs, PUPS, computer cookies, trackerware, heavy duty, homepage hijackers, keyloggers, LSP, tracks, trojans, spybots, revision, and other kinds of malware. It also has the ability to protect the user’s privacy by deleting usage tracks like tracking cookies.
Spybot-S&D is also equipped with an Immunize feature that blocks the installation of spyware before it occurs.
Another useful tool Spybot has is the file shredder which is used for the secure deletion of files.
Real-time protection from undesirable registry changes and the like is achieved by the Spybot’s TeaTimer module. The TeaTimer module is a pop-up which alerts the user to registry changes, and ask for approval before allowing the change. Registry changes are usually made when programs are modified either by installing, uninstalling or customizing, so random changes may mean that malicious software has penetrated your PC.
Some programs ship with attached spyware or adware and refuse to run when the undesired co-programs are removed; newer versions of Spybot replace the spyware binaries with inert dummies (designed to fool programs which require the spyware’s presence).
Weekly updates. Weekly updates are offered by Spybot to better protect you against malicious programs. Updates are downloaded from the software itself and is automatically installed.
 
Spybot Search and Destroy’s multifunction capabilities is what makes this free software an essential tool for every internet user.

Ad Aware - Spyware Blocker and Anti-virus

Developed by LavaSoft, Ad-Aware is a free, simple, and effective program that is designed to provide advance and effective protection against adwares and spyware.

Ad- Aware isn’t just limited to detecting unwanted programs but it also equipped to scan your RAM, registry, hard drives, external storage devices, and also for known data-mining, advertising, and tracking components and safely removes software that may pose a threat to your system.

Some of the ad programs Ad- Aware can remover are Adware, Aureate/Radiate, OnFlow, Comet-Cursor, Cydoor, Doubleclick, EverAd, Flyswat, and TimeSink.

Ad-aware can be regarded as one of the requisites of anyone using the internet to safe-guard there systems against possible threats.

Ad-aware is available in its standard edition for free. Other editions include the Plus and Professional editions which has more enhanced functionality where you need to purchase an end-user license.