Free anti-virus from AVG provides you with antivirus and antispyware protection for Windows. The most downloaded software on CNET's Download.com, its fast and effective.
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Malwarebytes - Traditional antivirus relies on outdated signature-based technology that addresses threats at the execution stage of the attack chain. It's reactive, one-dimensional, and apparently isn't effective. Malwarebytes employs several proprietary technologies that work together to break the attack chain, from pre-delivery to post-execution.
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Spybot - Search & Destroy detects and removes spyware. Anti-spyware is not commonly covered by anti-virus applications. It can also clean usage tracks if you don't want others to see what you have been working on.
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The industrial strength Zone Alarm firewall proactively protects your computer against inbound, outbound, and program attacks while making you invisible to hackers.
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TrueCrypt is free open-source disk encryption software. It can create virtual encrypted disks, encrypt an entire partition or storage device such as USB flash drive or hard drive. Encryption is automatic, real-time and transparent.
Truecrypt Home: : Download