Computer Viruses are widely known as evil programs that are meant to corrupt the peaceful environment of a computer. Actually a computer virus is a piece of programming code that alters the way your computer works without your knowledge or permission. They are often designed to replicate and spread quickly to other computer users. ComÂ¬puter Viruses do not generate by themselves. They must be written by someone and with a specific purpose.
A virus starts infecting another program, boot sector or document by attaching itself to that medium such that when an infected file is opened, the hidden virus is also executed, often in the background. Generally viruses cant move on to other computers by themselves. They must be passed on via infected email attachments, proÂ¬grams on disks or shared files.
Finding a virus is generally not easy, as they don't cooperate. A virus attempts to spread before activating whatever malicious activity they may have been programmed to deliver. So, viruses are often programmed to hide themselves. The symptoms of a system hit with a virus usually arrive only after a long time when the mission of a virus is almost over. Hence it is difficult even for a virus-expert to find a virus in a system without any antivirus tools, which are widely available nowadays.