Computer viruses are destructive programs that disrupt normal computer functioning. There are several types of viruses including boot sector viruses, file infector viruses, and macro viruses. Viruses can slow computers down, delete files, crash systems, and corrupt data. They spread by infecting files and devices and are downloaded from unauthorized websites. Symptoms of a virus include slow performance, frequent crashing, and file corruption. People should use antivirus software, avoid unsafe downloads and inserts, and regularly scan their systems to protect against viruses.

1. Computer Virus
2015/02/01
Presented by: Shubham Kafle
Class:-8

2. Introduction on virus
 The destructive computer program that disrupts the normal or
proper functioning of computer.
 A malware program.
 Invented by a famous American scientist Frederick B. Cohen.

3. Types of virus
 Bootstrap:
 Infects the booting device of the computer.
 File infector virus:
 Overwrites the files which it infects.
 Multipartite virus:
 It is the combination of Boot sector virus and file infector virus. It is the most
dangerous virus.
 Macro virus:
 This virus affects documents so virus is also known as document virus.
 Script virus:
 It is a denied code which is also called as polymorphic virus.

4. What a virus can do?
Virus have lots of effects on computer. It can do lots of things
like:
 It can destroy the computer programming.
 It can make the computer slow.
 It can delete the computer file and folders.
 It can restart the computer frequently.
 It can make the computer crash.
 It can corrupt the files and folders of the computer.
 It can leak the data to other to other computer.
 It can also not let the antivirus to be installed in the computer.

5. What a virus cannot do?
There are many things which a computer virus cannot do.
 It cannot damage the computer hardware.
 It cannot harm to the harm to human beings.
 It cannot damage the protected files and folders.
 It cannot bring our lost files and folders from the computer.
 It cannot damage the antivirus software or any other
computer protecting software.

6. Symptoms of Virus
When there is virus in our computer then we notice some
changes in our computer which are the symptoms of virus. The
symptoms are:
 Computer runs slow than usual.
 The computer stop responding or it locks up frequently.
 The computer crashes and then it restarts every few minutes.
 Application on the computer do not work correctly.
 The file may get corrupted.
 Some times some files and folders may get lost.

7. Spreading of Virus
Virus are spreaded to earn money through selling antivirus in
large amount. It spreads by following ways:
 A virus is spread whenever an infected program is run
 Once a virus is copied on a computer it attaches to other
application of computer
 By using infected devices such as:-flash drivers then a virus
can enter to a computer
 By downloading from an authorized website can also bring
virus to the computer

8. Protection from Virus
To keep our computer protected from virus we should apply following
ways:
 Keep a strong antivirus
 Don’t insert any pen drives or any other flash drives unless it is
virus free.
 Avoid downloading any software in a unauthorized website or free
of cost.
 Scan and update antivirus time to time.
 Keep your antivirus in high/maximum security.

9. Thank You!!