Computer Viruses and Security SS2 Computer Hardware & GSM Repair Lesson Note

Class: SS2

Subject: Computer Hardware and GSM Repair

What is a Computer Virus?

A computer virus isn’t a germ; it is a hidden program or a piece of code written by a person (a hacker) to cause trouble. Just like a flu virus needs a human body to spread, a computer virus needs a “host” (like a flash drive or an email attachment) to move from one computer to another.

The goal of a virus is usually one of three things:

1. To Annoy: Showing pop-up ads or changing your wallpaper.
2. To Destroy: Deleting your school projects or corrupting Windows.
3. To Steal: Copying your passwords or bank details.

Common Types of “Digital Pests”

Not every “sick” computer has a virus. There are different types of “Malware” (Malicious Software):

• The Virus: It attaches itself to a file (like a photo or a song). When you open the file, the virus “wakes up” and starts copying itself.
• The Worm: This is even scarier. It doesn’t need you to open a file. It “crawls” through the internet or a local network to find other computers to infect.
• The Trojan Horse: Named after the wooden horse in history. It looks like a helpful program (like a free game or a fake “speed booster”), but once you install it, it lets a hacker into your computer.
• Ransomware: This is like a digital kidnapper. It locks all your files with a secret code and demands that you pay money (a ransom) to get them back.
• Spyware: This “hides” in the background and watches everything you type—including your Facebook or Bank passwords.

How Does a Computer Get “Infected”?

Viruses don’t just appear out of nowhere. They need a “door” to get in:

1. Infected Flash Drives: Plugging a “friend’s” USB drive into your laptop without scanning it is the most common way viruses spread in schools.
2. Email Attachments: Opening a file from a stranger that says “You won a prize!” or “Urgent Invoice.”
3. Pirated Software: Downloading “cracked” games or movies from unofficial websites. These often come with hidden Trojans.
4. Fake Websites: Clicking on “Your computer is infected! Click here to fix it!” banners.

Symptoms of an Infected Computer

How do you know if your computer is “sick”? Watch out for these signs:

• The “Snail” Speed: The computer suddenly becomes very slow for no reason.
• Disappearing Files: You look for your assignment, and it’s gone or renamed to strange symbols.
• Strange Pop-ups: Ads appearing on your screen even when you aren’t browsing the internet.
• Self-Starting Apps: Your webcam light turns on by itself, or programs open without you clicking them.
• The “Blue Screen”: Frequent crashes or restarts.

Prevention: Being a “Digital Guard”

Prevention is always better than repair. Here is how to keep your computer safe:

• Install an Antivirus: Think of this as your computer’s “immune system.”
• Keep Software Updated: When Windows or Chrome asks to “Update,” say YES. These updates often include “security patches” that close the doors hackers use.
• Think Before You Click: If an email or a website looks “too good to be true,” it probably is.
• Scan Every USB: Never open a flash drive without right-clicking it and selecting “Scan with Antivirus.”
• Use Strong Passwords: Don’t use “12345” or your name. Mix letters, numbers, and symbols.

Popular Antivirus Tools

There are many tools to choose from. Some are free, and some are paid.

• Windows Defender: Built into Windows 10 and 11. It’s actually very good if you keep it updated!
• Avast / AVG: Popular free versions for home users.
• Kaspersky / Norton: Very powerful paid versions that offer extra protection for online banking.
• Malwarebytes: Great for “cleaning up” a computer that is already heavily infected.

Student Summary Table

Practical Lesson for Students

“Today, check your computer. Is Windows Defender turned on? When was the last time it did a ‘Full Scan’? If it’s been a month, start a scan now and see if any ‘digital pests’ are hiding in your files.”