These days you need more than just a virus protection. Only about 15% of all malware is viruses. The rest is worms, trojans, phishing schemes, spyware, etc.
Here's some ideas to "roll ya own" Internet Security Suite for free. Free is always the best.
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1. For your Anti-Virus......(Always use only 1 A-V...You must NEVER use more than one anti-virus, Even an expired anti-virus can cause a major conflict)
For your anti-virus needs, I would suggest Avira AntiVir® PersonalEdition Classic. It has excellent heuristics, a virus detection rate that is better than many of "paid-for" anti-virus programs and is light on using your computer's resources. And did I mention that it's free!
Download here:
http://www.free-av.com/
Avoid an anti-virus called AVG (free version). It is wildly popular but has poor virus detection rates.
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2. For your Firewall..........(Always use only 1 software firewall)
A decent free firewall that is PC Tools Firewall Plus. One can either choose "Normal User Mode" Or "Expert User Mode"'depending on the desired detail of alerts and application custom rules.
It is one of the few free firewalls that will work (and work well) on Vista as well as XP and 2000.
http://www.pctools.com/firewall/
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3. For your Anti-Adware and Anti-Spyware needs...............(use at least 1 anti-spyware, but 2 is OK):
SUPERAntiSpyware:
http://www.superantispyware.com/
Spybot Search and Destroy:
http://www.safer-networking.org/en/spybotsd/index.html
Ewido (now known as AVG Anti-spyware) Do NOT download AVG Anti-virus.:
http://ewido.com
AdAware 2007
http://www.lavasoft.de/software/adaware/
A-Squared:
http://www.emsisoft.com/en/software/free/
Windows Defender:
http://www.microsoft.com/athome/security/spyware/software/default.mspx
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4. And to help protect your computer from ever getting infected with malware in the first place............ (use them both)
SpywareBlaster helps to immunize your computer again certain selected malware.:
http://www.javacoolsoftware.com/spywareblaster.html
SiteAdvisor warns you when visiting a potentionally malicious web-site:
http://www.siteadvisor.com/
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5. And always keep your Windows 100% updated and patched with all critical and security updates from Windows Updates. THIS IS A MUST! In Internet Explorer just click Tools then Windows Updates.
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Everything here is 100% free!!!!!!
Great luck! Enjoy!