This list includes only well-known software manufacturers. For free downloadable antivirus tools please click on the free antivirus link on the left hand side of the page.

A-squared: The A-squared scanner checks for malicious pieces of software and for Trojan horses, backdoors, worms, dialers, adware-spyware, keyloggers, rootkits, hacking tools, riskware and tracking cookies. However, it only works inside IE (Internet Explorer) with ActiveX controls enabled.

BitDefender Scan8 Online: BitDefender is a complete online anti-virus scanner that appears in a new window. It requires IE to function.

Command On Demand Scanner: Another straightforward online virus scanner that requires IE and ActiveX controls.

The ESET Online Scanner: This online antivirus scanner from ESET also requires ActiveX and IE.

Computer Associates CA Anti-Virus: The free online version of their anti-virus program  requires ActiveX and IE.

Ewido Networks Anti-Spyware: Ewido Networks has an online anti-spyware scanner that is a predecessor to AVG Anti-Virus; it also requires IE and ActiveX.

Freedom Online Virus Check: One of the very few online scanners that works with both Firefox and IE.  Firefox users will need to install a Java-based scanner, while IE users will need to activate ActiveX controls The service's engine is based on the F-Prot scanner.

F-Secure Online Scanner: Another scanner that requires IE and ActiveX. It also checks for rootkits.

Panda ActiveScan: Based on the popular their virus scanner, the online version also requires IE and ActiveX.

Windows Live OneCare: Microsoft's online virus scanner is based around its new Windows Live technology — and yes, this service too is only compatible with Internet Explorer with ActiveX controls enabled.

Trend Micro HouseCall: A smarter online scanner than most, this solution detects browsers and installs the appropriate piece of code needed, whether it's Java or ActiveX. The service is based on TrendMicro's popular anti-virus engine.

Mcafee also has a free scan that is based on their award winning security and antivirus tools.

On this Symantec page you can check how secure your computer is or run the Norton online scanner for free.

Free Downloads for Windows XP, Free Games and simply FREE! Your source for Free Online Antivirus Scan and Security Checks.