Ad-Aware

http://www.downloaddossier.com/www/dl/index.php?dlid=7 

Ad-Aware Personal provides advanced protection from known data-mining, aggressive advertising, Trojans, dialers, malware, browser hijackers, and tracking components. This software is downloadable free of charge.

Registry Booster 

http://www.downloaddossier.com/www/dl/index.php?dlid=110 

Registry Booster, how does it work?

Residual files, unused and undeleted drivers, and corrupt or bad entries in registry settings will quickly litter even the newest of computers. The result? Frequent error messages, slow start-ups, declining and poor performance and registry integrity, unstable and frequent application errors and crashes, and, at times, even an inability to start Windows.

http://www.downloaddossier.com/www/dl/index.php?dlid=8 

AVG Free Edition is the well-known antivirus protection tool. AVG Free is available free of charge to home users for the life of the product. Rapid virus database updates are available for the lifetime of the product, thereby providing the high level of detection capability that millions of users around the world trust to protect their computers. AVG Free is easy to use and will not slow your system down (low system resource requirements). Highlights include automatic update functionality, the AVG Resident Shield, which provides real-time protection as files are opened and programs are run, free Virus Database Updates for the lifetime of the product, and AVG Virus Vault for safe handling of infected files.

http://www.downloaddossier.com/www/dl/index.php?dlid=115

RAM Def can defragment your RAM when reaching a warning level, or silently (with command-line parameters). It excels in terms of reliability and speed, and the full support it offers to its users, with help files, a troubleshooting guide, tips, online assistance, and a forum guarantees you peace of mind along with extreme performance.