VIRUS

VIRUS

Virus stands for VITAL INFORMATION RESOURCES UNDER SIEZE. A computer virus is an intrusive program. The virus affects computer files and folders Computer virus is a program or piece of code that is loaded onto your computer without your knowledge and runs against your wishes. It modifies other computer program by inserting a copy of itself inside them. When the program is loaded, the copies of the virus are executed to infect still other files.


Virus can also replicate themselves. Entire viruses are man-made . Even a simple virus is dangerous because it will quickly use all available memory and bring the system to a halt.


Viruses is created in order to gain an illegal entry into a computer and obtain or destroy some vital information. Computer virus is written in same programming languages that are used to create other computer programs.

Most viruses stay active in the memory until you turn off the computer. virus can remove from memory not from disk. So, the next time you use your computer the virus program is activated again. It may then attach itself to more programs and/or files. An even more dangerous type of virus is one capable of transmitting itself across networks and bypassing security systems.

HOW A COMPUTER VIRUS SPREAD?

A virus appear on a computer by itself.it spread through external sources like infected Floppy Disks, compact disks, Internet, E-mail attachments, infected pen drives etc. Biological virus spread when we share articles used by an infected person. Computer virus also spread when we share a copy of an infected file. We download or open infected files and programs or even e-mails.

Once a viruses enters a computer system, following are the various ways in which it spread:

Some viruses infect the system when the system is booted or when a file is copied from an infected Floppy Disk, pen Drives, CDs and DVDs.
Some viruses infect even when there is an attempt to erase the contents of an infected disk.
Viruses can also be passed from one computer to another when data or programs are accessed on a network or a file is downloaded from internet. Internet is the most common path for virus.
Viruses makes copies of it and also tries to carry out the harmful texts written in its program. After infecting a system, a viruses tries to take control of the system.It tries to attach itself to another program in order to spread. This process can happen so quickly that the user is not even aware of the presence of a viruses in his/her computer. also, viruses are programmed to activate at certain date/time. They check the system clock continuously and when the present matches the system time, they harm the computer system.

HARMFUL EFFECTS OF VIRUSES

Corrupting the data or program files.
Increasing the size of files by attaching themselves to the files.
Interference with the display.
Formatting the hard disk, thus destroying data.
spread from one computer to another.
Decreasing the speed of the computer by decreasing the memory
Frequent hanging of the system.
Displaying a change in data against the file name in the directing, when a virus modifies the file.