Computer viruses are small software programs that are designed to spread from one computer to another and to interfere with computer operation. A virus might corrupt or delete data on your computer, use your e-mail program to spread itself to other computers, or even erase everything on your hard disk. Viruses are most easily spread by attachments in e-mail messages or instant messaging messages. That is why it is essential that you never open e-mail attachments unless you know who it’s from and you are expecting it.
Viruses can be disguised as attachments of funny images, greeting cards, or audio and video files. Viruses also spread through downloads on the Internet. They can be hidden in illicit software or other files or programs you might download.
To help avoid viruses, it’s essential that you keep your computer current with the latest updates and antivirus tools.
We think you must have used many Antivirus programs, we are not talking about them in this post. There are some merits and demerits of all of them. But one thing is for sure. No Antivirus is perfect. By the very nature of their working principle, Antivirus invent the process of cleaning a virus only after a virus is born. And this gap, between invention of a virus and its vaccine decides the effectiveness of an anti virus software.
As we said above that no Anti virus program is perfect, then it is sometimes better to apply double protection, meaning that you you two anti virus programs to scan your PC. But you cannot use two anti virus programs simultaneously on one machine. So, why not try using free online antivirus programs?
Here we are introducing you to 10 best online free anti virus scan utilities:
1.) Trend Micro 
: HouseCall is a FREE Web-based tool designed to scan your PC for a wide range of Internet security threats including viruses, worms, Trojans, and spyware. It also detects system vulnerabilities and provides a link so you can easily download missing security patches.
2.) Panda Active Scan 
: Panda ActiveScan 2.0 detects all types of viruses, Trojans, worms, spyware, dialers, hacking tools, jokes, and other active or inactive (latent) security risks on your PC. It also detects vulnerabilities of software installed on your PC which could compromise your computer’s security.
3.) Computer Associates Virus Scanner 
: This scanner requires a browser such as Internet Explorer which is capable of rendering ActiveX objects.
4.) Symantec Security Check 
: Virus Detection checks for known threats, including top threats identified by Symantec Security Response. It provides an analysis of your results and offers suggestions for further action.
5.) McAfee FreeScan 
: McAfee FreeScan helps you detect thousands of viruses on your computer. Based on the award-winning McAfee VirusScan engine, FreeScan searches for viruses, including the latest known “in the wild” viruses, and displays a detailed list of any infected files.
6.) BitDefender Free Online Virus Scan 
: 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.