The second free tool from Symantec is called Virus Detection and it checks for known threats, including top threats identified by Symantec Security Response. Virus Detection provides an analysis of your results and offers suggestions for further action. It does not examine compressed files.

When Symantec receives notification about a new virus, they develop and post a solution as quickly as possible. We are committed to providing swift responses to all virus threats, including Trojan horse

4. F-Secure Online Scanner
It is also a free online virus scan service and you are advised by F-Secure  to find out if your computer is infected and disinfect your computer if needed. The size of the download package is about 18 megabytes including databases.
The F-Secure Online Scanner works with default Internet Explorer settings (Internet zone - Medium security level). If you have changed them, you may enable ActiveX and JavaScript from Tools->Internet
Options->Security->Custom Level.

5. Kaspersky Online Scanner
This free online virus scan is a great way to find out if you have any viruses or spyware on your machine without having to uninstall your current antivirus software or install a new one. Most importantly, you can see what viruses your current antivirus software let slip through! You just need to be online and using Internet Explorer.

This free online virus scanner is very powerful and scans your machine very deeply, so it could take hours to complete. Kaspersky suggests running it during a time of low activity. Take the Kaspersky Challenge and see what malware your current antivirus software missed - you maybe surprised.

One thing though :
The online virus scanner will not remove the malware from your machine if it finds it - installing Kaspersky software is required to do this. You can try the antivirus software (full product) for FREE by downloading and installing a free trial, or you can purchase our products in the estore.