I have included few free softwares for the better performance and better security. Most of them, I tested in my machine and they are good read about them read the privacy statements and use them if you want.
Currently am using
AVG Free Antivirus
Ad-aware
Spybot
Spyware Blaster
CCleaner (Crap Cleaner)
Tiny Personal Firewall
a-Squared Free
Active Security Monitor
Tiny Firewall is a security solution for the windows based host presented to general public to date. The suite of features covers the protection from various angles - from network security, file and registry protection, application launch control and management through signature based Intrusion detection and Prevention.
The firewall itself runs as a background service, using a special low-level driver loaded into the system kernel. This driver is placed at the lowest possible level above the network hardware drivers. Therefore, it has absolute control over all passing packets and is able to ensure complete protection of the system it is installed on.
It is paid now, but you can get the free old version
Here is the link
http://www.oldversion.com/program.php?n=tpfirewall
Zonelabs Personal firewall
Most popular free PC firewall product on the market.
Easy-to-use firewall blocks hackers and other unknown threats.
Here is the links
http://www.zonelabs.com/store/content/company/products/znalm/freeDownload.jsp
Spybot - Search & Destroy detects and removes spyware, a relatively new kind of threat not yet covered by common anti-virus applications. Spyware silently tracks your surfing behaviour to create a marketing profile for you that is transmitted without your knowledge to the compilers and sold to advertising companies. If you see new toolbars in your Internet Explorer that you haven't intentionally installed, if your browser crashes inexplicably, or if your home page has been "hijacked" (or changed without your knowledge), your computer is most probably infected with spyware. Even if you don't see the symptoms, your computer may be infected, because more and more spyware is emerging. Spybot-S&D is free, so there's no harm giving it a try to see if something has invaded your computer.
Here is the Link
http://www.safer-networking.org/en/mirrors/index.html
CCleaner is a freeware system optimization and privacy tool. It removes unused files from your system - allowing Windows to run faster and freeing up valuable hard disk space. It also cleans traces of your online activities such as your Internet history. But the best part is that it's fast (normally taking less than a second to run) and contains NO Spyware or Adware! 
Here is the Link
http://www.ccleaner.com/download/
AVG Anti-Spyware [Ewido Anti-Spyware]
Anti-Virus programs offer insufficient protection against urgently growing threats like Trojans, Worms, Dialers, Hijackers, Spyware and Keyloggers.
That's where the protection of AVG Anti-Spyware begins and supplements existing security applications to create a complete security system - because only a complete security system works effectively.
Here is the Link
http://www.ewido.net/en/download/
SpywareBlaster
Prevent the installation of ActiveX-based spyware, adware, browser hijackers, dialers, and other potentially unwanted software.
Block spyware/tracking cookies in Internet Explorer and Mozilla/Firefox.
Restrict the actions of potentially unwanted sites in Internet Explorer.
SpywareBlaster can help keep your system spyware-free and secure, without interfering with the "good side" of the web.
And unlike other programs, SpywareBlaster does not have to remain running in the background.
Here is the Link
http://www.javacoolsoftware.com/sbdownload.html
Active Virus Shield is free anti-virus for your PC that combines traditional antivirus programs, stopping them before they can infect your computer.
Active Virus Shield is brought to you as a free service of AOL and is based on Kaspersky Lab’s award winning Personal Anti-Virus:
Here is the Link
http://www.activevirusshield.com/antivirus/freeav/get_started.adp
Avira AntiVir PersonalEdition Classic reliably protects your private computer against dangerous viruses, worms, Trojans and costly dialers.
More than 15 million users worldwide trust in the reliable protection of Avira AntiVir. And this is no coincidence at all: Avira has gained several awards. The product combines first-class detection rates and ease of use with a top performance that protects your computer safely and hardly burdens older PCs.
Here is the Link
http://www.avira.com/en/avira-free-antivirus
BitDefender 8 Free Edition is your chance to use one of the world's most effective antivirus engines for free!
BitDefender 8 uses the same ICSA Labs certified scanning engines found in other BitDefender products, allowing you to enjoy basic virus protection for no cost at all.
Here is the Link
http://www.bitdefender.com/site/view/Download-Free-Products.html
avast! Home Edition is now free of charge for HOME users for NON-COMMERCIAL use. You can find more information here. If you are not a home user, or you use your computer for profit, the avast! Home Edition is not licensed for such use, and you are asked to use the commercial version - avast! Professional Edition.
To use the Home Edition, you should register it, however, after initial installation you have 60 days to trial the product (as with all avast! antivirus products) before you must complete registration. The registration process is very easy, and will take you only a couple of minutes.
Here is the Link
http://www.avast.com/eng/download-avast-home.html
AVG Anti-Virus Free Edition
GRISOFT is announcing a new version of the AVG Anti-Virus Free Edition. This new 7.5 version with improved performance and full compatibility with the latest Windows Vista version is available. Users that are using AVG Free 7.1 will be provided with a specific dialog, within the next few weeks, with the opportunity to choose the right option fulfilling their needs. AVG Free 7.1 version will be discontinued on 18th of Feb 2007.
Here is the Link
http://free.grisoft.com/freeweb.php/doc/5390/lng/us/tpl/v5#avg-anti-virus-free
AVG Anti-Spyware Free is a free anti-spyware protection tool developed by GRISOFT for home use. We invite you to join the millions of satisfied customers worldwide who have downloaded the software and now enjoy the benefits of AVG Anti-Spyware Free.
Here is the Link
http://free.grisoft.com/freeweb.php/doc/5390/lng/us/tpl/v5#avg-anti-spyware-free
MRU-Blaster is a program made to do one large task - detect and clean MRU (most recently used) lists on your computer.
These MRU lists contain information such as the names and/or locations of the last files you have accessed. They are located ALL OVER your registry, and for almost ANY file type. By looking at these MRU lists, someone could determine what files you opened/saved/looked at, what their file names were, and much more! (And, in many cases, the lists are displayed in drop-down menus automatically.)
Here is the link
http://www.javacoolsoftware.com/mrublaster.html
SpywareGuard provides a real-time protection solution against spyware that is a great addition to SpywareBlaster's protection method.
An anti-virus program scans files before you open them and prevents execution if a virus is detected - SpywareGuard does the same thing, but for spyware! And you can easily have an anti-virus program running alongside SpywareGuard.
Here is the Link
http://www.javacoolsoftware.com/spywareguard.html
ID-Blaster Plus
In Windows, many applications have something called a "product ID number", a "GUID" or a "Unique ID number". This number may be the same throughout Internet Explorer, Windows Media Player - even the operating system itself.
Since this number nevers changes, it would be the PERFECT way a malicious person or even an advertising company could track your habits - perhaps through a malicious website ActiveX control, or Java applet.
Why not just delete it, in this case, you would have a constant ID of nothing - and given the small number of people that might also have that "null" value, it could still be used to track you.
ID-Blaster Plus works by changing these ID numbers frequently, destroying tracking tactics using these numbers. ID-Blaster can run from the system tray, using very little resources, and constantly protect you in the background.
ID-Blaster Plus is compatible with Windows 95, 98, ME, NT, 2000, XP. Freeware/donationware.
Here is the Link
http://www.javacoolsoftware.com/idblaster.html
a-squared Free
Security must not be a privilege. Under this motto, Emsi Software provides the Malware scanner a-squared Free completely free of charge for private use. But it is not a very limited version, it is a full tool to clean your computer from Malware. Not only Spywares, as detected by classic Anti-Spyware programs, but also especially Trojans, Backdoors, Worms, Dialers, Keyloggers and a lot of other destructive pests, which makes it dangerous to surf the web.
Here is the link
http://www.emsisoft.com/en/software/free/
a-squared Anti-Dialer
No chance for the Dialer rip off! Protect your PC with a-squared Anti-Dialer from manipulated dial up connections, which can cause a phone bill of several hundred dollars quickly.
a-squared Anti-Dialer provides a complete defense against Dialers. Scan all files on your harddisks for Dialer behavior using the Dialer scanner. The integrated background guard protects the PC from new infections. As soon as a potential Dialer creates or manipulates a dial up connection, the a-squared Anti-Dialer will alert it.
Here is the Link
http://www.emsisoft.com/en/software/antidialer/
a-squared HiJackFree is a detailed system analysis tool which helps advanced users to detect and remove all types of HiJackers, Spyware, Adware, Trojans and Worms.
Here is the link
http://www.hijackfree.com/en/
Stinger is a stand-alone utility used to detect and remove specific viruses. It is not a substitute for full anti-virus protection, but rather a tool to assist administrators and users when dealing with an infected system. Stinger utilizes next generation scan engine technology, including process scanning, digitally signed DAT files, and scan performance optimizations.
Here is the link
http://vil.nai.com/vil/stinger/
IE Privacy Keeper
Whether you are using Internet Explorer or Mozilla Firefox, IE Privacy Keeper automatically cleans up the browser history once you are done surfing the net. The program will correctly clean up all index.dat files without the need for a Windows restart.
Here is the link
http://browsertools.net/IE-Privacy-Keeper/
Eraser is an advanced security tool (for Windows), which allows you to completely remove sensitive data from your hard drive by overwriting it several times with carefully selected patterns. Works with Windows 95, 98, ME, NT, 2000, XP, Windows 2003 Server and DOS.
Eraser is Free software and its source code is released under GNU General Public License.
Here is the link
http://eraser.heidi.ie/
From Microsoft The Sysinternals web site was created in 1996 by Mark Russinovich and Bryce Cogswell to host their advanced system utilities and technical information. Microsoft acquired Sysinternals in July, 2006. Whether you’re an IT Pro or a developer, you’ll find Sysinternals utilities to help you manage, troubleshoot and diagnose your Windows systems and applications. If you have a question about a tool or how to use them, please visit the Sysinternals Forum for answers and help from other users and our moderators.
Featured Resources
File and Disk Utilities
Utilities for viewing and monitoring file and disk access and usage.
Networking Utilities
Networking tools that range from connection monitors to resource security analyzers.
Process Utilities
Utilities for looking under the hood to see what processes are doing and the resources they are consuming.
Security Utilities
Security configuration and management utilities, including rootkit and spyware hunting programs.
System Information
Utilities for looking at system resource usage and configuration.
Miscellaneous Utilities
A collection of diverse utilities that includes a screen saver, presentation aid, and debugging tool.
Here is the Link
http://www.microsoft.com/technet/sysinternals/default.mspx
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