This is the latest beta release and is actually an old program that was made by GIANT Company Software Inc. but Microsoft has bought them out. and it has developed the software further.

Spybot - Search & Destroy 1.4

  Application to scan for spyware, adware, hijackers and other malicious software.

Ad-Aware Personal

  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.
 

AVG Antivirus Free Edition

  AVG Free for Windows is a free anti-virus protection tool developed by Grisoft for home use. Download the software and enjoy the benefits of AVG Free for Windows.

ewido anti-malware

  This setup contains the free as well as the plus-version of the ewido security suite. After the installation, a free 14-day test version containing all the extensions of the plus-version will be activated. At the end of the test phase, the extensions of the plus version are deactivated and the freeware version can be used unlimited times. The purchased license code of the plus version can be entered at any time.

Avast 4 Home Edition Free Version Antivirus

  avast! Home Edition is now free of charge for HOME users.

Kerio Firewall

  A highly recommended firewall, but like all good firewalls it requires some knowledge to be able to get it running at its best. Pick the advanced installation to have the best protection.

CPU-Z

  CPU-Z is a freeware that gathers information on some of the main devices of your system.

The 46 Best-ever Freeware Utilities