<\/span><\/h3>\n\n\n\nVirus<\/em><\/strong> stands for Vital Information Resources Under Seize<\/em><\/strong> is a harmful program, that, on entering a computer, starts creating copies of itself. It then attacks by corrupting the executable files and folders saved on the computer. Similar to a biological virus, a computer virus cannot travel on its own; it needs to be attached to some other program or executable file to move from one computer to another. In short, a computer virus is a malicious program that enters your computer, replicates itself (creates copies of itself), and damages the computer by corrupting files and folders. Different types of viruses are:<\/em><\/strong><\/p>\n\n\n\n\n- Boot Sector Virus-<\/em><\/strong> This type of virus infects the master boot record of the system by either moving it to another sector or replacing it with infected ones.<\/li>\n\n\n\n
- File Infecting Virus-<\/em><\/strong> This type of virus infects the executable files or files containing executable code such as .exe, .com, .dll, .sys, etc.<\/li>\n\n\n\n
- Polymorphic Virus-<\/em><\/strong> This type of virus changes its code when as it propagates from one file to another. Therefore, each copy that it generates appears different from others. This makes the polymorphic virus difficult to be detected by the Antivirus software.<\/li>\n\n\n\n
- Stealth Virus-<\/em><\/strong> This type of virus attempted to conceal its presence from the user and\/or Antivirus software by using various techniques.<\/li>\n\n\n\n
- Multipartite Virus-<\/em><\/strong> This type of virus infects both boot sector and executable files and uses multiple mechanisms to spread itself. It is the worst virus of all because it can combine some or all of the stealth techniques along with polymorphism to prevent detection.<\/li>\n<\/ul>\n\n\n\n
The usual symptoms of a virus attack are as follows:<\/em><\/strong><\/p>\n\n\n\n\n- The computer begins to run slowly.<\/li>\n\n\n\n
- Unusual messages and graphics appear on the computer screen for inexplicable reasons.<\/li>\n\n\n\n
- Music not associated with any of the open programs begins to play.<\/li>\n\n\n\n
- Some programs or data files on the computer either become corrupt or are difficult to locate.<\/li>\n\n\n\n
- Unknown files or sub-directories are created.<\/li>\n\n\n\n
- The size\/dates of executable files change on their own.<\/li>\n\n\n\n
- The volume label of your hard disk changes mysteriously.<\/li>\n\n\n\n
- Hardware devices begin to exhibit unusual behavior.<\/li>\n<\/ul>\n\n\n\n