Online virus scanner is an on-demand
BitDefender Online Scanners
BitDefender Online Scanner is an on-demand virus scanner which incorporates the award-winning BitDefender scanning engines. You can use it to scan your system's memory, all files and drives' boot sectors, and to automatically clean infected files.
http://www.bitdefender.com/scan8/ie.html
ESET Online Scanners
The ESET Online Scanner is a user friendly, free and powerful tool which you can use to remove malware from any PC utilizing only your web browser without having to install anti-virus software. The ESET Online Scanner uses the same ThreatSense® technology and signatures as ESET NOD32 Antivirus, and is always up-to-date.
http://www.eset.eu/online-scanner
Panda Security Online Scanners
Panda Active-Scan is a powerful online antivirus that scans your computer for viruses, free of charge, with just a simple click from your browser. ActiveScan is updated constantly, giving it the ability to detect even the latest viruses. Main features include: ability to detect and eliminate over 185,000 viruses, spyware, trojans, hackers-tools, jokes, rootkits, phishing, hoaxes, spam and other Internet threats with automatic daily updates; Virus scan of e-mail and shared files. Online operation, no need to install the complete program, simply download the ActiveX controls. To get to know more about ActiveScan, click here: