best free antivirus

Avira Anti Virus Personal Edition
AntiVir is very light on resources and the detection rate of malware is outstanding, better than almost every other antivirus according to tests. However, there are some reservations.

First, AntiVir does not include web or e-mail scanning capabilities; this is only available in the paid version. The lack of an e-mail scanner is not really a disadvantage, it just means that AntiVir won't warn you of infected emails before you open them. But should you open an infected email, AntiVir will still spring into action, so it doesn't mean that you're not protected from email-based infections. Second, AntiVir has advertisements that appear with every update, although you can disable these ads. Finally, AntiVir has a time-limited license. It is renewable, but be aware that you'll have to periodically go through the hoops. Although AntiVir had signature updating problems in the past this seems to be fixed now.

Microsoft Security Essentials


Microsoft Security Essentials has good detection rates, in particular detecting rootkits. Even more impressive is that Security Essentials has very few false positives, is light on resources and is good at removal of existing malware.

Microsoft Security Essentials is the best choice for average users because of the minimal user interaction required. It automatically updates and removes threats. No registration is needed, apart from a quick validating of Windows, and there are no nag screens or advertisements.

The main downsides are the slow scan speeds and the lengthy amount of time it takes to quarantine malware. MSE also is not available in certain countries so users there will have to look elsewhere. Note that Microsoft Security Essentials requires a genuine copy of Windows to install.


Avast! Free Antivirus

Avast! Free Antivirus is also an excellent free antivirus that many users prefer. Its detection rates is on par with AntiVir. Avast has the most features, with full real-time capabilities, including web, e-mail, IM, P2P and network shields, boot-time scanning, and a behavioural blocker. Avast is light on resources.

These free antivirus programs are excellent software that provide a real alternative to the major commerical antivirus products.

You can increase your protection if you run on-demand scans with another antivirus. On-demand scans can be run regularly to check for viruses, trojans, worms, spyware, adware, keyloggers, rootkits and other malware that may have been missed by your main antivirus scanner. If you have a good preventive security strategy in place, however, the extra protection an on-demand antivirus scanner offers is minimal.

You can also use one of the free antiviruses mentioned above as an on-demand antivirus scanner. One advantage is that you can set scheduled scans if you wish.

Comodo internet security

Comodo Antivirus

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  Detect and destroy existing malware, viruses, worms, and other unwanted PC invaders.

  
  
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  Comodo Antivirus
  Advanced 2011

  Go beyond ordinary PC protection with Comodo Antivirus Advanced 2011.

• Internet Security

  
  

  Suite of cutting edge security including Antivirus, Firewall, malware prevention and more.Free Download
  
  
  

  PC Tools^™ AntiVirus Free 2011
  Free AntiVirus Protection

  

  • Protection
    Basic antispyware and antivirus protection while you’re working, surfing and playing
  • File Guard
    File Guard scans and blocks malware in real-time
  • Search Defender
    Search Defender, built on Browser Defender technology, warns you about unsafe or phishing websites
  • Smart Updates
    Smart Updates automatically check for updates against the latest threats
  • Free Antivirus Software
    It's FREE! PC Tools believes everyone has the right to basic protection

  Basic FREE antivirus protection against known viruses and malware.

  With PC Tools AntiVirus Free, you are protected against basic cyber threats attempting to gain access to your PC. Don't risk going online without protection. Dangers include virus infections or getting your identity stolen - download PC Tools software today for enhanced protection!
  If your PC gets infected, viruses may attempt to spread to your friends, family and associates by accessing your email contacts and other PCs within your network. A computer virus may also create a backdoor that allows hackers to access files on your PC, launch attacks against other computers or websites, or send SPAM email.
  Downloading PC Tools AntiVirus Free provides basic antivirus and antispyware protection, with Smart Updates to keep your PC safe, File Guard™ to provide real-time protection and Email Guard to protect your computer from viruses and spyware being sent over email. PC Tools AntiVirus Free was created by the makers of award-winning Spyware Doctor, a highly trusted product used by millions worldwide.
  

  What's new in PC Tools AntiVirus 8?

  • Better protection, better scanner, less impact Our focus for PC Tools AntiVirus 7 was to provide enhancements in protection, detection and scanning.
    This has been achieved through the introduction of next generation sliding signatures, specifically designed to better cater for the significant numbers of threat variants in the wild. PC Tools' next-gen sliding signatures have also delivered performance improvements to scan time and system impact with a further reduced memory footprint and overall system impact during scanning.
  • Virus Scan and Removal for MBR PC Tools AntiVirus 7 has advanced functionality for virus scan and removal of the boot sector viruses that infect Master Boot Record (MBR).

  PC Tools AntiVirus Features

  PC Tools AntiVirus' main features include the following:
  

  • IntelliGuard protection against computer viruses and related malware threats PC Tools AntiVirus detects and eradicates viruses and related malware threats that attempt to enter computer systems by means of file transfer through storage media, e-mail, the Internet and other network protocols. Protection is provided by means of on-demand system scanning or real-time (IntelliGuard) detection of threats.
    
  • Smart Updates to keep virus definitions and other feature enhancements up to date Smart Updates are released frequently, allowing you to protect your system against the latest virus and related malware threats, as well as improvements to PC Tools AntiVirus' functionality. By running Smart Update regularly, you can help keep your system free of new infections.
    
  • Customizable Scan Settings applicable to both PC Tools AntiVirus' on-demand file scan and real-time protection features Scan settings are easily configurable and apply both to the on-demand scans and IntelliGuard scans (detection in real-time through the IntelliGuard tool). These scan options allow you to customize a range of generic and global settings which affect the overall behavior of PC Tools AntiVirus.
    
  • Ability to quarantine and restore items that have been detected PC Tools AntiVirus allows you either to remove detected viruses and related malware from your system or to quarantine them into a contained area. The majority of infections that have been quarantined can be restored at a later time. You can customize PC Tools AntiVirus either to remove or to quarantine malware items fixed in a scan.
    
  • Logging of File Scans conducted by PC Tools AntiVirus All File Scans conducted by PC Tools AntiVirus can be logged, providing a record of when each scan was conducted; the infections that were identified; and when infections were disinfected, quarantined or removed.
    
  • Enhanced architecture providing enhanced infection removal capabilities for limited user accounts PC Tools AntiVirus' service-based architecture allows user accounts with limited permissions to scan all areas of the operating system to ensure thorough removal of viruses and other related malware threats.
    

  Minimum System Requirements

  • Intel Pentium 300 MHz processor (or equivalent) or better
  • 256 MB of RAM
  • 40 MB of free hard disk space
  • Internet Explorer 6 or greater