Computer Virus by Neeraj Bhandari ( Surkhet.Nepal )
What is computer virus?
Computer virus refers to a
program which damages
computer systems and/or
destroys or erases data files.
Types of Computer Virus
• Boot SectorVirus
• Program virus
• Macro viruses
Boot Sector Virus
This type of virus affects the boot
sector of a hard disk.
This is a crucial part of the disk, in
which information of the disk itself is
stored along with a program that
makes it possible to boot (start) the
computer from the disk.
These viruses infects program files
which have extensions such as
.COM,.EXE,.SYS,.DLL,.OVL or.SCR .
Program files are attractive targets
for computer virus because they are
widely used and have relativity
,simple formats to which viruses can
Macro viruses as the name implies, will
infect files of programs that use macros
in the program itself.The most common
of these are the Microsoft Office files
created in Excel spreadsheets, Word
documents, Access databases,
PowerPoint presentations and these type
of files from AmiPro and Corel Draw and
What a computer virus do?
A virus tries to take control of computer
system it has infected at the first opportunity
It makes copies of itself and also try to carry
harmful task written in its program.
This process can happen so quickly that the
user is not even aware of the presence of a
virus in his/her computer.
Norton antivirus is a product of Symantec
corporation founded in 1982.
Norton check the following program
• Boot records
• Programs(at the time you used them)
• All local hard drives,
• Files download from internet,
• USBs (when in use)
MacAfee virus scan
McAfee Inc. is an antivirus software
headquartered in Santa Clara, California.
The company was founded in 1987 as McAfee
Associates, named for its founder John
McAfee who resigned from the company in
In February 28, 2011, McAfee is wholly
owned subsidiary of Intel.
KasperskyAnti-Virus is an antivirus program
developed by Kaspersky Lab
It is designed to protect user
from malware and is primarily designed for
computers running Microsoft
Windows and Mac OS X
KasperskyAnti-Virus features include real-
time protection, detection and removal
Avast is a freemium antivirus computer
program available to Microsoft
Windows, Mac OS X and Linux users, with
a user interface available in 41 languages.
AVAST Software has headquartered
in Prague, Czech Republic, with offices
in Linz, Austria, Germany and San Mateo,
Panda Cloud Antivirus
Panda Cloud Antivirus is antivirus software
by Panda Security which are available in a
free and a paid version
According to Panda Security, Panda Cloud
Antivirus is able to detect viruses,Trojans,
worms, spyware, dialers, hacking tools, jokes
and other security risks.
Over 100 million customers,Avira is
considered the sixth largest antivirus vendor
Avira periodically "cleans out" the virus
definition files, by replacing specific
signatures with generic ones, resulting in a
general increase in performance and