COMPUTER VIRUSES ON COMPUTER

One of ongoing problems in the computer field is the introduction to computer viruses by antisocial users. A computer virus is a program containing code that can generate multiple copies of itself. Viruses have the potential to destroy and disrupt computer systems and computer networks. It may or may not damage data or other programs residing in the computer system. Viruses are made to do many different things like making innumerable copies of themselves, erasing storage devices, data corruption, data loss and displaying message or graphics. It is the intellectual creation of a computer programmer. Computer viruses are written to affect your computer adversely without your knowledge. Viruses can easily hide within a system by attaching themselves to other files or programs because they are small in size. The ability of a virus to replicate enables it to infect files and programs.

Computer virus is a destructive computer program that disrupts the normal functioning of the computer. They have ability to replication and execute themselves. They use to hide themselves in other files and damage data, files, programs, etc. of a computer. The number of computer viruses is increasing day by day. The number of computer viruses varies from each other. Some viruses increasing the size of files by adding some unnecessary texts or codes. The computer virus like “HTML.Redlof.A” adds unnecessary vbscript codes in the web files. Some viruses decrease the size of files by removing texts. Some viruses change the FAT of a disk (i.e. dislocate the data, files, and programs) so files and programs cannot be loaded.

Computer viruses are developed in order to destruct data, files, programs and to disrupt the normal functioning of a computer. The amount of destruction caused by viruses varies widely. Viruses can do the following

Some of the features of a computer virus are listed below:

1. The computer virus may cause problems immediately.
2. It may count specific occurrences, for examples, how many times it is copied, and then cause damage.
3. It may look at the computer’s clock and cause damage on a specific date.
4. It may reproduce itself and then cause damage.
5. Destroy data, information, software and hardware. Some viruses destroy the boot sector of the disk. Some destroy the File Allocation table, so that the file becomes inaccessible.
6. Degrade the overall performance of the computer system.
7. Steal important data and information.
8. Load and run unwanted applications.
9. Send documents via electronic mail (e-mail).
10. Display the unnecessary messages.
11. Change the size of files by adding or removing texts or codes.
12. Cripple a machine’s operating system.
13. Replicate and spread on the other files or programs.
    

A computer virus can spread from one computer to other computer in many ways. Viruses usually enter the computer system through external sources like infected floppy disks, compact disks, pen drives and the Internet. The various ways through which computer viruses spread are:

• Sharing of infected floppy disk, pen drive, or compact disk.
• Opening of virus infected e-mail messages and attached files.
• Downloading files or programs from the Web or from the internet services.
• Exchanging of data over a network.
• Using pirated software.

Normal programs are your assistants. Virus programs are written with a motive to cause trouble and harm. A computer virus is usually activated when the program or file to which it is attached is executed or accessed. Viruses spread by the use of infected data or programs residing in the disk while copying them from one system to another. They also spread by getting attached to e-mail messages or by flow of other forms of information on the Internet. The way in which a virus replicates and spreads from one computer to another depends upon the way it is programmed to behave. Different viruses behave in different ways. Some stay active in memory until the computer is shut down. Other viruses stay active only as long as the infected application is running.