F-Secure Online Virus Scanner
F-Secure is a free online virus scanner service. You can use it to find out if your computer is infected with a virus and disinfect your computer if needed. The service requires you to download a temporary executable file that is around 4 megabytes. Please note that F-Secure will scan your system for viruses only. It is not set up to find malware, spyware or adware. The service will work on the following operating systems: Win 98, ME, 2000 and XP Home Edition. It also only supports Internet Explorer 5.0 or higher. You must have JavaScript and ActiveX enabled in I.E. for it to run. While this service is not as powerful as Panda ActiveScan, it does have one cool feature that can be really useful in a pinch. F-Secure allows you the option of scanning your whole hard drive or just a single file. The single file feature is great for doing a quick scan on the fly and can save you a ton of time especially when you are in a virus removal help forum.

Panda ActiveScan
This powerful, easy to use free web based virus removal tool scans your computers local hard drive and detects and disinfects, eliminates viruses it finds there. Panda ActiveScan is completely safe to use. It detects and eliminates more than 110,000 known viruses, worms, Trojans and their variants. It scans for viruses in emails and compressed files...is updated every day and can even be setup to warn you when new viruses appear. The basic version of Panda ActiveScan is 100% free. Panda is a very useful tool for those that do not have an antivirus program installed on their system...or do have one...but it has been disabled by a virus attack. The only drawback with Panda is that it only supports Internet Explorer 5.0 or higher. Editors note: Panda now also detects spyware, adware and malware.

Free Full Featured Antivirus Software

AVG Free Anti-Virus Software
AVG is an outstanding freeware anti-virus utility and a MUST have for anyone surfing the internet. In fact we can honestly say it is the very best program we've ever used...Free or Commercial.

AVG's most important feature is it's ability to detect not only common viruses but also spyware and malware including Cool Web Search (CWS) and other browser hijackers. The free version of AVG also offers updates of virus definitions every other day. The updates can be set to run automatically in the background so it's virus definitions are never out of date.

The program's initial installation and setup is straight forward and worked flawlessly from start to finish on all operating systems we tested. AVG includes a custom installation feature for more advanced users where they can pick and choose the options and tools they need for their systems setup. It also allows users to add options to the program on the fly after installation...without having to uninstall first.

AVG's standard tools and options are extremely powerful yet, simple to master, even for a new computer user. Many of AVG's optional tools are actually separate programs with-in the main program shell. Some of the programs more intuitive features include: a Resident Shield that monitors your system for viruses 24/7 and allows you to virus check a single file from your right click menu.  A full functional email scanner that checks both incoming and out going messages. An integrated Scheduler that automates AVG scans and updates. An air tight and fully controlled Virus Vault where you can safely view information on viruses removed by the program. Detailed, yet easy to read Log files with information on AVG actions on your system and much more.

All in all, AVG is an excellent free option for any computer user wanting a powerful yet easy to administer, front line antivirus protection program.
Download AVG. For Win 95, 98, Me, NT, 2000 and XP | Linux | File size 1.3 MB. Editors note: AVG is free for personal, home use only. Businesses wishing to use the program must purchase a license. We have been using this program on all our servers for over two years. We highly recommend it as your frontline defense against virus attacks!

avast! 4 Home Edition
avast! 4 Home Edition from ALWIL Software, is a full-featured antivirus package designed exclusively for home users and non-commercial use. Both of these conditions need to be met to use the product for free. ALWIL offers the Home Edition free of charge because they believe "it is possible to avoid global virus spreading by efficient prevention". We couldn't agree more. In fact, we believe that all antivirus software should be free for non-commercial use.

With that off our chests, avast! 4 Home Edition is a very well thought out antivirus package that incorporates many powerful features including it's ease of installation and user interface for non-technophile users. Power users will also find the program very useful as well with it's feature rich components that include: 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 and more. See site for a complete breakdown of the above features list.
Download avast! 4 Home Edition. For Win 95, 98, Me, NT, 2000, XP and Vista | File size 7.1 MB. Editors note: You must register with a valid working email address to get this program for free. The program will work for 60 days after installation in demo mode. You will obtain a free license key by email after the registration. The license key is valid for 1 year. After one year you will need to re-register to keep the software operating and free.

BitDefender 8 Free Edition
BitDefender 8 Free Edition is 100% freeware. It uses the same ICSA Labs certified scanning engines found in other (for cost) BitDefender products. BitDefender 8 Free Edition is an on-demand virus scanner, which means it should not be used as your front line virus protection solution. It is however, a great second line of defense as studies have proven that a layered approach to virus and spyware and adware protection is now preferable. This is because even the best antivirus programs will miss a detection now and then. Running two different products will give you the best chance of keeping your system clean.

Product features in BitDefender 8 Free Edition include: Virus scanning and removal, Scheduled scanning, Immediate scanning, Skinable interface, Quarantine and Scan process Reports and more.

The one drawback to BitDefender 8 Free Edition is that it does not offer any email virus scanning or protection.
Download BitDefender 8 Free Edition For Win 98, Me, NT sp6, 2000 and XP | File size 8.8 MB.

Free Antivirus Search and Databases

Symantec Security Response
Symantec provides a free synopsis of the latest virus-related threats including information on: Category Rating (risk), Name of Threat (threat), the day on which the threat was identified (discovered), and the day on which a virus definition was added to protect against the threat (protection). You can search for viruses alphabetically or view their complete database of viruses and variants.

F-Secure Virus Description Database
The F-Secure computer virus description database is administered by their support team. The database is updated several times a week. F-Secure's virus description service was started in 1994. They claim it was the first antivirus web site on the Internet - and is considered the industry standard source for up-to-date information on new viruses and hoax alerts.

AVG Virus Encyclopedia
Avg offers a simple search box on this page where you can type in the virus you are looking for and it will query their entire virus encyclopedia.