Virus Warning Signs – JSS3 Computer Studies Lesson Note (Third Term)

Warning signs of a computer virus are changes in how a computer behaves, such as pop-ups, slow running, missing files and crashes.

Behavioural objectives

By the end of the lesson, students should be able to:

1. Define a computer virus.
2. List the warning signs of a computer virus.
3. Recognise when a computer may be infected.
4. State the steps to take when a computer is infected.
5. State the protective measures against a computer virus.

What is a computer virus?

A computer virus is a harmful program that copies itself and spreads from one computer to another, damaging files or slowing the system.

• Effect: it can delete or corrupt files, slow the computer and steal information.
• Spread: it moves between computers without the user knowing.
• Anti-virus software: a program that detects, blocks and removes viruses.
• Operating system (OS): the main software that runs the computer, such as Windows or Android.

How does a computer virus spread?

A computer virus spreads through shared files, storage devices and the internet.

• Email attachments: opening a file from an unknown sender can start the virus.
• Flash drives: a drive used on an infected computer can carry the virus to another one.
• Unsafe downloads: files from unknown websites may hide a virus.
• Infected websites: some sites install harmful programs when you visit or click them.
• Pirated software: copied programs may carry a virus with them.

What are the warning signs of a computer virus?

There are eight common warning signs of a computer virus, grouped by what the user notices.

Signs in how the computer runs

• Slow running: programs take a long time to open and the computer seems to hang.
• Unusual crashes or error messages: the computer restarts or shuts down by itself, or shows errors often.
• Unusual hard drive or SSD access: the drive light blinks or the disk works hard when you are doing nothing.

Signs on the screen

• Unexpected pop-up windows: advertisements or warnings appear without you opening anything.

Signs in files and storage

• Missing storage space: free space on the drive falls quickly for no clear reason.
• Files going missing: documents, pictures or programs disappear or cannot be opened.

Signs on the network and email

• Excessive network or internet activity: data is used heavily even when you are not browsing.
• Strange emails from your address: friends and family tell you they received messages you did not send.

Does every warning sign mean the computer has a virus?

No, a warning sign only shows that a virus may be present.

• Slow running: can also come from too many open programs or a full drive.
• Crashes: can also come from faulty hardware or outdated software.
• Pop-ups: some come from websites you visit and not from a virus.
• Best action: if several signs appear together, treat the computer as infected and scan it.

What should you do if you think your computer has a virus?

If you think your computer has a virus, cut it off from the internet and scan it with anti-virus software.

1. Disconnect from the internet, so the virus cannot spread or send out your data.
2. Reboot into safe mode, which starts the computer with only the basic programs.
3. Install anti-virus software if the computer has none.
4. Run a full scan and remove anything the software finds.
5. Clear the browser cache.
6. Get in touch with a service professional if the signs continue.

What are the protective measures against a computer virus?

Protective measures are habits and tools that keep viruses out of a computer.

• Install anti-virus software: it checks files and blocks threats.
• Run a full scan from time to time: this finds viruses that came in unnoticed.
• Update your browser and operating system (OS) regularly: updates close weak points that viruses use.
• Clear the browser cache: this removes stored web data from the browser.
• Disconnect from the internet when infected: this limits the damage.
• Reboot into safe mode: this makes a virus easier to remove.
• Get help from a service professional: an expert can clean a badly infected computer.
• Be careful with unknown files: do not open attachments or plug in drives from sources you do not trust.

Evaluation

1. Define a computer virus.
2. List five warning signs of a computer virus.
3. Name three protective measures against a computer virus.
4. What should you do to your internet connection if you think your computer has a virus?
5. Which two things should you update regularly to protect your computer?

Assignment

Draw a table with two columns, “Warning signs” and “Protective measures”, and fill in all the points given in this lesson.