Ch 5 : Computer Virus

Grade 7 Computer Studies: Computer Viruses & Prevention

1. What is a Computer Virus?

A Computer Virus is a harmful computer program written by humans to damage, steal, or slow down data inside a computer system.

Just like a biological virus makes a person sick, a computer virus makes a computer system malfunction.

Full Form of VIRUS:
Vital Information Resources Under Seize

Common Symptoms of an Infected Computer:

  • Runs very slowly.
  • Shows sudden pop-up messages or strange errors.
  • Files or folders disappear automatically.
  • Computer restarts on its own.

2. Who Created the First Computer Virus and Why?

The First Virus: Creeper (1971)

  • Creator: Bob Thomas
  • Why it was created: It was built as an experimental test to see if a program could automatically move between different computers. It was not meant to destroy data—it simply printed the message: "I'm the creeper, catch me if you can!"

The First PC Virus: Brain (1986)

  • Creators: Two brothers from Pakistan, Basit Farooq Alvi and Amjad Farooq Alvi.
  • Why it was created: To protect their medical software from illegal copying (piracy). It unexpectedly spread globally via floppy disks.

3. How Does a Computer Virus Spread?

Computer viruses cannot spread by themselves without a carrier path. They spread through these primary channels:

Transmission Channel How It Spreads
Infected USB Drives Plugging an infected pen drive or hard drive into a clean computer.
Email Attachments Opening suspicious file attachments sent by unknown senders.
Unsafe Downloads Downloading free movies, cracked games, or software from untrusted websites.
Pirated Software Installing pirated or modified software that contains hidden viral code.

4. How to Prevent Computer Viruses

  • Use Genuine Antivirus: Install and regularly update reliable security software.
  • Scan External Drives: Always scan USB drives before opening files.
  • Avoid Unknown Links: Do not click on suspicious links or download random attachments from emails.
  • Keep Software Updated: Regularly update the computer's Operating System (e.g., Windows Updates) to fix security weaknesses.
  • Backup Data: Store important files on external drives or cloud storage like Google Drive.

5. Antivirus Software, Uses, and Examples

Antivirus Software is a specialized security program designed to detect, block, and remove computer viruses and malware.

Key Functions:

  1. Real-time Protection: Scans files automatically as they are opened or downloaded.
  2. System Scanning: Checks all hard drive files for existing infected code.
  3. Quarantine & Removal: Isolates infected files to keep them from spreading, then cleans or deletes them.

Popular Antivirus Examples:

  • Windows Defender (Built into Windows OS)
  • Kaspersky Antivirus
  • Avast Free Antivirus
  • Quick Heal
  • Norton Security

Classroom Discussion Questions

  1. If a computer suddenly becomes very slow and loses files, what might be the cause?
  2. Why is using a friend's USB drive without scanning it dangerous?
  3. What is the main difference between a computer virus and an antivirus program?