This document discusses computer viruses and how to prevent them. It defines a computer virus as a program that damages computer systems and destroys or erases data. It outlines several common types of viruses like time bombs, logical bombs, worms, boot sector viruses, macro viruses, script viruses, and Trojan horses. It describes the characteristics and behaviors of each virus type. Finally, it provides recommendations for preventing virus infections, such as updating antivirus software weekly, backing up important data, using file encryption, installing security updates, and turning on a firewall.

1. Topic: Computer Virus
Submitted by: Mithun kumar Cse 4rd year

2. Contents
1. What is computer virus?
2. Types of computer virus.
3. prevents from computer virus.

3. What is computer virus?
• Computer virus is a program
which damages computer
system and destroy/erase all
data.

4. Types of computer virus
1. Time bomb
2. Logical bomb
3. Worm
4. Boot sector virus
5. Macros virus
6. Script virus
7. Trojan horse

5. Time bomb virus
• A time bomb is virus
program that performs an
activity on particular
date/time.

6. Logical bomb virus
• A logical bomb is a
destructive program that
perform an activity when
certain action has occurred.

7. Worm virus
• A worm is also
destructive program that fills
computer system with self-
replacing information, clogging
system and slow down the
system.

8. Boot sector virus
• A boot sector virus
infects boot sectors of computer
system. during the boot system,
boot sector virus loaded in main
memory and destroy all data
from memory.

9. Macro virus
• A macro virus
associated with application
software like word and excel.
• when open macro virus then it
loaded in main memory and
destroy data from hard disk.

10. Script virus
• Commonly script
virus written in visual
basic scripting edition (.vbs)
and java programming.

11. Trojan horse virus
• A Trojan horse virus is
destructive program.
• It usually associated with games
and computer software
application.
• Executed and destroy all data.
• Trojan horse is also comes with
key logger and monitoring tool.

12. Action to prevent
virus infection
• Update antivirus.(weekly).
• Backup important data.
• Don’t share c: drive .
• Empty floppy drive before turning
on/off system.
• Don’t open unexpected email
attachment.

13. Action to prevent
virus infection
• Use file encryption.
• Install security updates.
• Use multiple backup.
• On Secure browsing.(Firefox)
• Turn on firewall.

14. Thank you