Just come across with few web site which provide the free service for malware scanning. It is a very good idea where we should try to scan any unknow or possible malware affected files before we actually open it.
Some of the web site which provide the free downloading software, e-Book may also contains possible malware which may affect your computer, so it’s good idea to scan on that web site before actually access or download any file from there.
Virus Total: http://www.virustotal.com
Comodo: http://camas.comodo.com
Jotti: http://virusscan.jotti.org
There are actually more and more free tools out there, please feel free to command and share with me if you have come across with any useful online virus scanning tools. sharing is caring.