Computer viruses are harmful programs that spread like biological viruses. The first computer virus, called BRAIN, infected boot sectors of floppy disks in 1986. Viruses spread by attaching to other files when they are exchanged or downloaded. They can slow down or crash systems by erasing files or formatting disks. Antivirus software and regular updates help prevent viruses, along with avoiding unknown file attachments or downloads.

1. Computer virus !!!!!
Prepared by
Pratik pandya

2. What is computer virus ?????
 computer viruses are a type of software program that harmful for the system,
Like a biological virus, produce and spreads itself
 Some virus may display only a message on the screen ,
Others may slow down the PC
 They can also erase files or even format your floppy or hard disk and crash
the system

3. FIRST COMPUTER VIRUS
 BRAIN is the industry standard name for a computer virus that was released in
its first form in January 1986 and is considered to be the first computer virus
for MS-DOS
 If infects the boot sector of storage media formatted with the DOS file
allocation table(FAT) file system
 BRAIN was written by two brothers , BASIT FAROOQ ALVI & AMJAD FAROOQ ALVI
from LAHORE, PAKISTAN
 Brain affect the IBM pc computer by replacing the boot sector of a floppy disk
with a copy of the virus

4. How to spread virus
 Computer viruses spread by attaching themselves to other computer program
files
 When you exchange a file or pen drive with a viruses, the virus spreads from
one computer to the another
 Viruses also spreads when someone attach his/her hard disk with your
computer
 When you download some data from the fake site
 And you download attachments from someone e-mail

5. Various types of viruses
 Memory Resident Virus==
These viruses fix themselves in the computer memory and get activated
whenever the OS runs and infects all the files that are then opened.
 Direct Action Viruses==
The main purpose of this virus is to replicate and take action when it is
executed. When a specific condition is met, the virus will go into actionn and
infect files in the directory or folder that are specified in the AUTOEXEC.BAT
file path. This batch file is always located in the root directory of the hard
disk and carries out certain operations when the computer is booted.
 Overwrite Viruses==
A virus of this kind is characterized by the fact that it deletes the information
contained in the files that it infects, rendering them partially or totally
useless once they have been infected.
 Worms==
A worm is a program very similar to a virus; it has the ability to self-replicate
and can lead to negative effects on your system. But they can be detected
and eliminated by an antivirus software.

6.  Trojans==
Another unsavory breed of malicious code are Trojans or Trojan horses, which unlike
viruses, do not reproduce by infecting other files, nor do they self-replicate like worms.
In fact, it is a program which disguises itself as a useful program or application.
 Web Scripting Virus==
Many web pages include complex codes in order to create an interesting and interactive
content. This code is often exploited to bring about certain undesirable actions.
 FAT Virus==
The file allocation table (FAT) is the part of a disk used to store all the information about
the location of files, available space, unusable space, etc
 Polymorphic Virus==
Polymorphic viruses encrypt or encode themselves in a different way (using different
algorithms and encryption keys) every time they infect a system. This makes it
impossible for antivirus software to find them using string or signature searches
(because they are different in each encryption). The virus then goes on to create a
large number of copies

7. How Viruses Can Damage our Computer
 There are many different types of viruses and all of these behave in slightly
different ways. They will all affect your computer differently. Viruses
commonly cause your computer to slow down and can also result in the loss of
important files.
 Some viruses can also compromise the security of your computer. These allow
hackers to view your personal information which could leave you open to
identity theft.

8. Prevention step
 Install an antivirus software
 Regularly update the program
 Open email attachment files only if you are expecting the attached files or
the sender is know and has confirmed sending file
 Try to avoid downloading and installing software from internet
 Install only registered copies of software or license software on the system

9. ANY QUESTION ???????

10. THANK U

11. DETAIL
 R.k university
Rajkot ,GUJRAT,
INDIA
 EMAIL=PRATIK PANDYA18@GMAIL.COM