What is a Computer Virus? :: A Computer Virus is a program or programming codes and set of codes which are composed, designed and written by software Developers or programming engineer to hurt or infect other computers locally or in PC systems network. They are capable of contaminating and infecting other PC by duplicating or reproducing itself as a natural biological virus. A portion of them are innocuous while different viruses can harm or damage computer system seriously and can harm computer client and users to an extent. Computer viruses can replicate itself and infect different computer shockingly and without any information to computer user or client, they can hide themselves and attack aggressively when comes in contact to "HOST"

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What is a Computer Virus

2.  What is a Computer Virus? :: A Computer Virus is a
program or programming codes and set of codes which are
composed, designed and written by software Developers or
programming engineer to hurt or infect other computers
locally or in PC systems network.
 They are capable of contaminating and infecting other PC
by duplicating or reproducing itself as a natural biological
virus. A portion of them are innocuous while different
viruses can harm or damage computer system seriously
and can harm computer client and users to an extent.
 Computer viruses can replicate itself and infect different
computer shockingly and without any information to
computer user or client, they can hide themselves and
attack aggressively when comes in contact to "HOST“

3.  They are spread by utilizing infected or contaminated
media when these infected media is taken to uninfected
computer it get infected or by downloading Documents,
videos, pictures, and content from the internet which
contains malicious programs.
 The Known First computer virus was developed by two
Pakistani Brothers from Lahore in 1986 and named it
as 'BRAIN VIRUS'

4. Different Types Of Computer Viruses
The computer viruses can be
classified in Following types ::
 System Virus
 File Viruses
 Boot Sector or Boot Record
Viruses

5. System Virus
 System Viruses are computer program or software codes
which resides and lives inside the system area of the hard
disk or any other media which contains MBR (Master Boot
Record),they infects the boot area of system, and various
other locations of the Operating systems.
 They mainly try to infect or contaminate boot files namely
command.com,Io.sys and Msdos.sys these are the
system files which carries out the boot process of a
working operating system.

6.  They are computer program which resides inside the system
area of the hard disk or any other media which contains
MBR (Master Boot Record),they infects the boot area of
system, and various other locations of the Operating
systems.
 They mainly try to infect boot files namely
command.com,Io.sys and Msdos.sys these are the system
files which carries out the boot process of an operating
system.
 They basically try to infect the input and output functions of
computer systems. They even can remain or dwell in the
system area & can do its work of contaminating and infecting
other system records which are critical and cruical to run the
boot procedure of computer system

7. Trojan Viruses
 Trojan Horses is a malicious program designed,
developed, planned and created to harm the computer
system. The codes are customized such that when it
interacts with some other program or documents it
changes them into Trojan virus.
 They control and perform the task of controlling and
manipulating the critical files of working system it infect
and harms File Allocation Table of HARD DISK DRIVES
which contains important and crucial data of Computer
system [PC].

8. Macro Viruses
 These are a tiny program which is composed inside
information files . Which can be attached to any files, for
example, text or even graphics, for example, pictures,
images or videos which are not harmful as different other
types of viruses.
 These types of viruses don't infect program files, for
example, .EXE or.COM they contaminate application
program, for example, word or speed sheets. They are
the most widely recognized viruses seen nowadays. They
are created to harm application program.
 Regular scanning of hard disk must be done, checking
and scanning of viruses from removable disk such as
DVD CD and pen drives or external computer hard disk
must be done periodically.

9. Worms
 A worm is a bit of code which is customized such that it
replicates itself when interacts with other different
computers in the network.
 Worm more often that not harm computers when
connected to each other via networking.
 These type of viruses which are attached to files or
programs and harm or manipulate the system files which
are available in your computer systems.

10. File Viruses
 These programs infect executable files and records such
as .EXE and.COM. They at times change the extension of
the file and make them useless.
 These viruses are attached to the start or the end of the
executable files and records, they don't harm data files
and do not make any manipulation Inside the files and
usually, change the functionality and performance of the
executable files.
 They change the programmed code of the executable
files and documents. which are written and composed for
a specific, particular and special task to perform and
hence abnormal set of instruction is executed when
someone runs them

11. Boot Sector or Boot Record Viruses
 The Boot sector or Boot Record Viruses are additionally
called as "PARTITION VIRUS“. The computer starts from
the boot area of the hard disk which is 0, 0.1 sector of
computer hard disk drive [HDD].
 In this sector, vital boot records are stacked which causes
a computer to start or boot the operating system. This
code in boot sector stacks in partition table and PC hard
drives have partition table which is a basic part which
loads the working operating system.

12.  As they stay active in memory, therefore, they can be
called as 'MEMORY RESIDENCE VIRUS' these
programs or codes contaminate clean startup records and
executable files to wreck the boot procedure of operating
system and even can erase the information present in the
computer hard disk.

13. Removal and Precautions Taken
Against Computer Viruses?
 They have become smarter these days, and even can
make a fool of good antivirus software and are developed
by the programmers who want to harm the computer
system.
 They reside in the memory and do all the functions they
have been developed for. They tend to hide themselves in
such a fashion that it is very difficult to eliminate them
after infection
 Never ever try to open or copy data from an unknown
source before doing so scan it with good antivirus
program which is updated and can eliminate or remove
any malicious program or virus-like activity from your
computer system.

14.  One Should always use legal antivirus Software.
 Regular Update of such antivirus must be done periodically.
 Never try to open or download from unknown Websites or
copy any files, documents, images, videos and content from
infected USB Drives and CD's or DVD's.
 Never visit pornographic websites as they contain malicious
program which can hurt or damage system files or operating
system.
 One must not download pirated software which may contain
malicious program.
 You must scan any USB medium before using.
 Always beware of phishing attacks generally happens when
clicked on websites which are not authenticated.

15. Thank you All
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