Free AntiVirus for Windows
ClamWin is one of several free antivirus programs availabe for Windows. What makes ClamWin unique is that it is GPL software. This means that it is free, and open source. ClamWin runs in your system tray, and can perform regularly scheduled system scans in addition to scanning Microsoft Outlook e-mail, and allowing you to right click any file and select 'Scan with ClamWin Free Antivirus'.
ClamWin is based off the widely acclaimed ClamAV project. According to their website "Clam AntiVirus is an open source (GPL) anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail gateways. It provides a number of utilities including a flexible and scalable multi-threaded daemon, a command line scanner and advanced tool for automatic database updates. The core of the package is an anti-virus engine available in a form of shared library." ClamAV is the antivirus engine of choice for open source enthusiasts but it is used in popular commercial antivirus products as well.
ClamWin is hosted at SourceForge.net. All you have to do to get up and running with ClamWin is to download and install it. Once installed a small tray icon will appear. Clicking on the tray icon will open the ClamWin main screen:
From the main window, you can select Tools -> Preferences to open the configuration screen:
The configuration screen allows you to set up scheduled scans, enable e-mail alerts and specify where alerts should be sent and via what mail server. The configuration screen also allows you to specify how a scan is run, and what files and directories to search and ignore.
The entire ClamWin tool is extremely straightforward and effective. Given the price tag there's not reason not to install ClamWin if you don't have any other AV products installed. Best of all ClamWin doesn't do real time scanning so it won't bog down your computer constantly looking at files while you're browsing the internet or composing a document. Although ClamWin doesn't offer some advanced features it is still an extremely valuable tool.