Practical: Virus Removal – JSS2 Computer Hardware & GSM Repair Lesson Note (Second Term)

Virus removal is the process of using antivirus software to find harmful programs on a computer and clean them out.

Behavioural objectives

1. State what antivirus software is and name three common antivirus programs.
2. Install an antivirus program on a computer in the correct order of steps.
3. Choose and run a Quick Scan, Full System Scan or Custom Scan.
4. Explain what Quarantine, Delete and Repair mean when a virus is found.
5. Follow safe habits when using USB flash drives and the internet in the computer lab.

What is antivirus software?

Antivirus software is a program that finds, blocks and removes computer viruses and other harmful programs.

• Purpose: it works like medicine for a sick computer, so the computer does not need to be thrown away.
• Detects: it checks files and programs against a list of known viruses.
• Cleans: it removes or isolates any harmful file it finds.
• Protects: it warns you before an infected file can do damage.

What are common antivirus programs?

Some antivirus programs are free and some must be paid for.

• Windows Defender: usually already inside your Windows computer (now shown as Microsoft Defender Antivirus in Windows Security).
• Avast or AVG: both have good free versions.
• Kaspersky or Norton: very strong programs, usually paid.

Important rule

• Use one only: never install two different antivirus programs at the same time.
• Reason: they interfere with each other and the computer becomes very slow.

How do you install antivirus software?

Installing antivirus means copying the program onto the computer and updating it, and it takes five steps.

1. Get the setup file: download it from the official website, or use a CD or USB provided by your teacher.
2. Run the installer: double-click the setup file (it usually ends in .exe).
3. Follow the instructions: when the window opens, click “Install” or “Next”.
4. Wait: the computer copies the files and may ask you to restart to finish the job.
5. Update: click the “Update” button, because an antivirus only works well if it knows the newest viruses.

What is a virus scan?

A scan is a check made by the antivirus program to search the computer or a drive for viruses.

Step 1: Choose the scan type

There are three types of scan: Quick Scan, Full System Scan and Custom Scan.

• Quick Scan: checks the most common places where viruses hide, in about 2 to 5 minutes.
• Full System Scan: checks every corner of the hard drive and can take about an hour.
• Custom Scan: checks only the place you choose, for example a USB flash drive.

Quick Scan compared with Full System Scan

Step 2: Run the scan

1. Open the antivirus program.
2. Click the “Scan Now” button.
3. Wait and watch the progress bar until the scan ends.

Step 3: Deal with the threat found

When the antivirus finds a virus, it usually gives three choices: Quarantine, Delete or Repair.

• Quarantine: puts the virus in a “digital jail” where it cannot harm anything. This is the best choice.
• Delete: removes the file completely. Use it when you no longer need the file.
• Repair: tries to remove the virus from the file and keep your data.

How do you stay safe from viruses in the computer lab?

Safe habits stop a virus before it enters the computer.

• The flash drive test: before opening any file from a friend’s USB drive, right-click the drive icon and choose the antivirus scan option (for example “Scan for Viruses”).
• Fake alerts: if a window pops up saying “Your Computer is Infected! Click here to fix”, do not click it. It is usually a trap to give you a virus.
• Trusted program only: trust only the antivirus program installed on the computer.

When should each antivirus action be done?

How do you scan with Windows Security?

Windows Security is the antivirus built into Windows 10 and Windows 11, so no extra software is needed.

1. Click the Start button and type “Windows Security”.
2. Open it and click “Virus & threat protection”.
3. Click “Quick scan” to start a quick check.
4. Click “Scan options” to choose Full scan or Custom scan.
5. If a threat is found, choose the action offered, such as removing it or quarantining it.

Class practical task

1. Open the antivirus program on your lab computer.
2. Check when the last “Update” was done.
3. Insert a USB drive and perform a “Custom Scan” on it.
4. Tell the teacher if any “threats” are found.

Teacher’s note

• Windows 10 or 11 labs: show students Windows Security to demonstrate every step without downloading extra software.
• Check first: make sure only one antivirus program is active on each lab computer.

Evaluation

1. Why should you not have two antivirus programs on one computer?
2. What is the difference between a Quick Scan and a Full System Scan?
3. What does it mean to quarantine a virus?
4. Why is it important to update your antivirus regularly?

Assignment

In your notebook, write the steps you would follow to scan a friend’s USB flash drive, and say which action you would choose if a virus is found.