Here is our list of trustworthy and free online antivirus scanners:

F-Secure's Online Virus Scanner
McAfee's freescan
Panda Software's ActiveScan
Symantec's Security Check
Trend Micro's HouseCall
Web Root's Spy Audit

Another useful tool is Stinger, which is a stand alone virus scanner. With Stinger, you download the application and then click on the icon. There is no install on the host machine. All the virus definitions are self-contained. As Stinger is updated regularly to check for more recent computer threats, you will always want to download the most recent version.