An Internet connection is needed on the other hand to perform the scan which sometimes can be a problem if the system is not booting into the operating system. A Live CD could help but many Online Virus Scanners demand the Internet Explorer which is obviously unavailable on Linux systems.

Online Virus Scanners can be used to get a “second opinion” without having to install another anti-virus software on the computer. It is probably a good idea to use as many of the virus scanners as possible if it is suspected that the system was infected by a virus. Below is a list of services that provide access to online virus scanners.

Bitdefender Online Scanner – requires Internet Explorer 4+

Eset Online Scanner – requires Internet Explorer

F-Secure Online Scanner – works only with Internet Explorer 6+

Kaspersky Free Virus Scan – browser independent, downloads roughly 25 Megabytes of files prior to scanning. User can select locations to scan. The scanner does not remove infected files.

McAfee FreeScan – requires Microsoft Internet Explorer 5.5+

Microsoft OneCare Live – requires Internet Explorer.

Panda ActiveScan – requires Internet Explorer or Firefox, does not run in Opera.

Shields Up! – browser independent but very slow and unresponsive currently.

Symantec Security Check – down or gone.

Trendsecure HouseCall – Java based scanner, works with Java compatible browsers.

Windows Security – Trojan scan that requires Internet Explorer 5+

File Scanners:

Avast Online Scanner – file size limit of 512 Kilobyte

Virus Scan – file size limit of 10 Megabyte.

Virus Total – email upload option, 10 Megabyte file size limit.

Do you know any other services where users can scan files or the computer ?