Free trojan scanner service. The program runs in your browser (IE and Windows only). By the way; a trojan is a program that enters your computer undetected, giving the attacker who planted the Trojan unrestricted access to the data stored on your PC.

McAfee FreeScan helps you detect thousands of viruses on your computer. Based on the award-winning McAfee VirusScan engine, FreeScan searches for viruses, including the latest known "in the wild" viruses, and displays a detailed list of any infe

Free online antivirus service to combat viruses, spyware and other Internet threats.

Test your computer's exposure to online security threats and learn how to make your computer more secure by symantec's free online service.

Trend Micro HouseCall is an application for checking whether your computer has been infected by viruses, spyware, or other malware. HouseCall performs additional security checks to identify and fix vulnerabilities to prevent reinfection.

Take the Kaspersky Challenge: See what your current antivirus is missing.