Microsoft Essentials.

Use Microsoft Security Essentials to guard against viruses, spyware, and other evil software. It provides real-time protection for your home or small business PCs.

http://windows.microsoft.com/en-US/windows/products/security-essentials

Avira-AntiVir-Personal-Free-Antivirus.

Our entry-level antivirus eliminates many forms of malware, including worms, rootkits and costly dialers.

http://download.cnet.com/Avira-AntiVir-Personal-Free-Antivirus/3000-2239_4-10322935.html?part=dl-10322935&subj=dl&tag=button&cdlPid=11012914

Avast.

Free antivirus with anti-spyware protection for Windows 7, Vista, or XP. avast! Free Antivirus has better detection than competing paid-for products!

http://download.cnet.com/Avast-Free-Antivirus/3000-2239_4-10019223.html?part=dl-85737&subj=dl&tag=button

Stinger.

McAfee Stinger detects and removes prevalent Fake Alert malware and threats identified in the "List Viruses" section of the Stinger application.

http://vil.nai.com/vil/stinger/

Avira-AntiVir-Personal-Free-Antivirus Rescue Disk

http://www.avira.com/en/download/product/avira-antivir-rescue-system/product/avira-antivir-rescue-system/product/avira-antivir-rescue-system

AVG Rescue CD......AVG Rescue CD is a comprehensive toolkit that will repair system crashes and return systems to a state where they can operate at full capacity, thanks to deep-rooted infections having been removed and file systems repaired.

http://www.avg.com/ww-en/avg-rescue-cd

HitmanPro 3 (32-bit)

http://download.cnet.com/HitmanPro-3-32-bit/3000-2239_4-10895604.html?tag=mncol;1

HitmanPro 3 has an intuitive interface that makes it easy to get started. If you're ready to plow ahead with the default scan, just click Next. If you'd like to do some customizing, the Settings button will take you to a variety of menus that let you control how the program operates.

HitmanPro 3 (64-bit)<

http://download.cnet.com/HitmanPro-3-64-bit/3000-2239_4-75110395.html?tag=mncol;2

Redistribution file. you need to install a more up-to-date version of Microsoft Internet Explorer or Microsoft Installer, both of which should be avaliable through Windows Update, assuming you're on a supported version of Windows, such as Windows XP.

http://faux.warwickcompsoc.co.uk/vcredist/

Glary-Utilities.

Glary Utilities offers numerous powerful and easy-to-use system tools and utilities to fix, speed up, maintain and protect your PC. Includes powerful functions such as registry fixer,disk cleaner,privacy protector,system info, disk analysis,etc.

http://download.cnet.com/Glary-Utilities/3000-2094_4-10508531.html?tag=mncol

Clam AV.

Looking for free Open Source Antivirus for Windows? Download ClamWin Free Antivirus and get free virus scanning and free virus definition updates.

http://www.clamav.net/lang/en/download/win32/

Trend Micro House Call.

HouseCall is a free virus scanner offered by Trend Micro, which checks whether a computer has been infected by viruses, spyware, or other malware.

http://housecall.trendmicro.com

SuperAntiSpyware

Free Edition is a comprehensive program that can scan and delete spyware and a variety of other types of malware. Although the program cannot deal with true viruses, it's capable of finding and annihilating plenty of other pests.

http://download.cnet.com/SuperAntiSpyware-Free-Edition/3000-8022_4-10523889.html

Malwarebytes

Anti-Malware Free utilizes Malwarebytes powerful technology to detect and remove all traces of malware including worms, trojans, rootkits, rogues, dialers, spyware and more.

http://download.cnet.com/Malwarebytes-Anti-Malware/3000-8022_4-10804572.html

AVG.

Free antivirus and anti-spyware security software for Windows. Get free antivirus protection now!

http://download.cnet.com/AVG-Anti-Virus-Free-Edition/3000-2239_4-10320142.html?part=dl-10044820&subj=dl&tag=button&cdlPid=11014801

Auslogics Registry Cleaner.

Auslogics Registry Cleaner is one of the best free computer registry cleaners available on the market. It will clean and fix registry errors for free.

Auslogics Registry Cleaner

http://download.cnet.com/Auslogics-Registry-Cleaner/3000-2094_4-10909814.html?tag=mncol;2

ReFlect Hard Disk Image Creator.

Backing up your computer shouldn't be a tedious task. Macrium Reflect Free Edition makes file backup incredibly easy thanks to its intuitive user interface and helpful wizards.

http://download.cnet.com/Macrium-Reflect-Free/3000-2242_4-10845728.html?tag=mncol;2

Microsoft Safety Scanner.

The Microsoft Safety Scanner is a free downloadable security tool that provides on-demand scanning and helps remove viruses, spyware, and other malicious software. It works with your existing antivirus software.

http://www.microsoft.com/security/scanner/en-us/default.aspx

Kapersky Rootkit Killer. Kaspersky TDSSKiller.

Detect and remove common rootkits in seconds. Kaspersky Lab has developed the TDSSKiller utility that allows removing rootkits.

http://support.kaspersky.com/downloads/utils/tdsskiller.zip

Hirem's Boot Disk.

Hiren's Boot CD is an all-in-one bootable CD solution that contains a load of useful tools you can make use of in a variety of situations.

http://www.hirensbootcd.org/download/

TrueCrypt

Free open-source disk encryption software for Windows 7/Vista/XP, Mac OS X, and Linux.

http://download.cnet.com/TrueCrypt/3000-2092_4-10527243.html