There are quite a few free anti-virus software programs that you can download for free.

Here are the ones we use and recommend:

• ClamAV
• ClamWin
• F-Prot Antivirus
• AVF Anti-Virus Free Edition
• AntiVir Personal Edition Classic
• avast! Home Edition
• BitDefender Free Edition
• BitDefender Linux Edition
• VCatch Basic
• Comodo AntiVirus

ClamAV

Clam AntiVirus is a GPL anti-virus toolkit for Unix. The main purpose of ClamAV is the integration with mail servers (attachment scanning). ClamAV provides a flexible and scalable multi-threaded daemon, a command line scanner, and a tool for automatic updating via Internet. The programs are based on a shared library distributed with the Clam AntiVirus package, which you can use with your own software.

Clam AntiVirus works with Linux, Solaris, FreeBSD, OpenBSD, NetBSD, AIX, Mac OS X, and Cygwin B20 on multiple architectures such as Intel, Alpha, Sparc, Cobalt MIPS boxes, PowerPC, and RISC 6000.

Most importantly, the ClamAV virus database is kept up to date.

• Command-line scanner
• Fast, multi-threaded daemon
• Mail filter interface for sendmail
• Database updater with support for digital signatures
• Virus scanner C library
• On-access scanning (Linux and FreeBSD)
• Detection of over 38000 viruses, worms and trojans
• Built-in support for Zip, Gzip, Bzip2, tar, RAR, MS OLE2, MS Cabinet files, MS CHM (Compressed HTML), MS SZDD
• Support for mbox, Maildir and raw mail files
• Support for Portable Executable files compressed with UPX, FSG, and Petite

ClamWin

ClamWin is a Free Antivirus for Microsoft Windows 98/Me/2000/XP/2003. ClamWin provides a graphical user interface to the Clam AntiVirus engine.

ClamWin Free Antivirus comes with an easy installer and open source code at no cost. It features:

• Scanning Scheduler
• Automatic Virus Database Updates. ClamAV team updates Virus Databases on a regular basis and almost immediately after a new virus/variant is out
• Standalone Virus Scanner
• Context Menu Integration to Microsoft Windows Explorer
• Add-in to Microsoft Outlook

F-Prot Antivirus

F-Prot Antivirus products are easy to use, reliable and demand little of the user's system resources. With their combined speed and reliable detection methods, F-Prot Antivirus products are the ideal computer security solution for home users.

F-PROT Antivirus for Linux, BSD, Solaris, and DOS are all free for home users.

AVF Anti-Virus Free Edition

The AVG Free Edition anti-virus protection tool is available free-of-charge to home users for the life of the product. Rapid virus database updates are available for the lifetime of the product, thereby providing the high-level of detection capability that millions of users around the world trust to protect their computers. AVG Free is easy-to-use and will not slow your system down (low system resource requirements).

• Automatic update functionality
• The AVG Resident Shield, which provides real-time protection as files are opened and programs are run
• The AVG E-mail Scanner, which protects your e-mail
• The AVG On-Demand Scanner, which allows the user to perform scheduled and manual tests
• Free Virus Database Updates for the lifetime of the product
• AVG Virus Vault for safe handling of infected files

AVG Free Edition is for private, non-commercial, single home computer use only. Use of AVG Free Edition within any organization or for commercial purposes is strictly prohibited.

AntiVir Personal Edition Classic

The private and individual use of the AntiVir Personal Edition is free of charge.

The AntiVir Personal Edition offers the effective protection against computer viruses for the individual and private use on a single PC-workstation. In order to make possible an easy operation, the AntiVir Personal Edition is developed to the essential points.

• Detects and removes more than 150,000 viruses
• Always among the winners of comparison test featured in computer journals
• The resident Virus Guard serves to monitor file movements automatically, e.g. downloading of data from the internet
• Scanning and repair of macro viruses
• Protection against previously unknown macro viruses
• Safeguard against cost generating dial-up program
• Protection against trojans, worms, backdoors, jokes and other harmful programs
• Easy operation
• Internet-Update Wizard for easy updating
• Protection against previously unknown boot record viruses and master boot record viruses
• Quality "Made in Germany"
• Support is free of charge via AntiVir Bulletin Board

avast! Home Edition

avast! Home Edition is now free of charge for home users for non-commercial use.

avast! Home Edition supports Windows 95 and higher.

avast! Home Edition Features:

• Antivirus kernel
• Automatic updates
• Simple User Interface
• Virus Chest
• Resident protection
• System integration
• P2P and IM Shields
• Integrated Virus Cleaner
• Network Shield
• Support for 64-bit Windows
• Web Shield
• Internationalization

BitDefender Free Edition

BitDefender Free Edition offers a scan engine with high detection rate, a friendly user interface and support for all e-mail clients.

BitDefender Free Edition automatically updates itself under Windows 2000 and XP; if a new user has logged in, even with restricted user rights, the software displays warning messages when new viruses occur.

BitDefender's behavior based search enables it to recognize unknown viruses and mutants. BitDefender also recognizes many file formats, archives and compressed files, embedded OLE objects in Office documents and runtime packers.

BitDefender features include:

• Virus scanning and removal
  • On demand scanning - Powerful scan engines ensure detection and removal of all viruses in the wild every time you need it.
• Scheduled scanning
  • The Scheduler lets you plan ahead, and schedule full system/drive scans in the off hours, when you won't be using your computer.
• Immediate scanning
  • With just a right click you can check your files and folders.
• Skinable interface
  • You can express yourself, designing new interfaces, or you can use those drawn by others.
• Quarantine
  • By isolating the infected files in quarantine, the risk of getting infected diminishes. You also have the possibility to send these files for further analysis to BitDefender Labs.
• Reports
  • When launching a scan you may choose to create a report file where you can see statistics about the scan process.

BitDefender Linux Edition

BitDefender Linux Edition uses the most advanced multi-platform virus inspection technology which scans for viruses and other malware on your personal system.

The On-Demand Scanner, for command line or shell scripts, features manual scan of individual files or entire file systems, malicious code detection and disinfection. After each scan, the solution displays a detailed report on positive virus detections. Thanks to BitDefender scan engine advanced features, new, undiscovered threats can be detected and immediately eliminated from the system.

BitDefender Linux Edition has the task of keeping you away from worms like Morris or Scalper - Unix malware, as well as from all the Windows viruses.

BitDefender Linux Edition is a free product, which does not require a license to be used.

• Antivirus scanning - on-demand scanning of the hard disk content
• Signature update - enables the update of the signatures files
• Quarantine zone - the infected files can be isolated on a secure area
• Increased scanning speed - owing to the new improved scanning engines
• Detailed reports and statistics - if configured, it will create a log file that will contain all the scanning results help - the user can view the help containing the protection options directly from the command line

VCatch Basic

VCatch is a new, free tool, developed to protect your computer from web viruses. Whether you use an Email application, Web based Email, ICQ, or one of the new file-sharing programs (iMesh, KaZaA etc.); VCatch is the tool for you.

VCatch is a virus protection software. When VCatch is active it will check all the files sent or downloaded to your computer via E-mail and Web applications. When VCatch detects that a file is suspected to be a virus, the software automatically deletes the file and notifies you.

VCatch supports Microsoft Outlook, Outlook Express, Eudora and Netscape Messenger. In Addition, VCatch protects your computer from viruses downloaded using IE or Netscape Navigator web browsers, files sent to your computer by ICQ, and files downloaded using file-sharing software such as iMesh and KaZaA.

VCatch has a unique automatic update mechanism. When a new virus is detected on the Internet, VCatch automatically updates its virus definitions list in your computer. Once you install VCatch, you don't have to do anything else to be constantly protected.

VCatch uses a combination of techniques to protect your computer. VCatch Internet professional searchers are responsible for constantly updating the viruses list so VCatch can keep the mail messages and the files containing them out of your computer. In addition, VCatch uses the Advanced Malicious Application Detection system (called "APayya"), which scans every incoming file looking for suspicious characteristics using a sophisticated and flexible rules system. VCatch enables you to set the preferred security level and uses these settings when a suspicious file is detected in order to decide whether to notify you. This way you can be sure you are protected both from known viruses and from unknown malicious applications.

Comodo

Comodo AntiVirus leverages multiple technologies (including on demand and on access scanning, email scanning, process monitoring, worm blocking and host intrusion prevention) to immediately start cleaning or quarantining suspicious files from your hard drives, shared disks, emails, downloads and system memory.

Updated virus definitions are automatically downloaded according to a schedule of your choice or by a single click on the 'updater' button. Once installed, Comodo AntiVirus will unobtrusively sit in your system tray, silently and efficiently defending your system from the latest virus outbreaks.

It's easy to install and configure, will not slow down your PC by hogging system resources and is free for life to the end user.

Comodo AntiVirus includes an application called LaunchPad. LaunchPad notifies users of free software offerings from Comodo. Some users have complained that LaunchPad is adware and is impossible to uninstall without removing Comod AntiVirus.