Removing a virus: complete guide to getting rid of malware

Is your computer slow, are you seeing strange pop-ups, or is your system acting oddly? Then there is a good chance your computer is infected with a virus or other malware. In this detailed guide you'll learn step by step how to remove malware and make your computer safe again.

Signs that your computer has a virus

Before we start removing anything, it's important to recognize when your computer is infected.

Common symptoms

Watch out for these warning signs:

  • Slow performance: Your computer is suddenly much slower than usual
  • Pop-ups: You see ads and pop-ups, even when no browser is open
  • Unknown programs: Programs you don't recognize have been installed
  • Browser changes: Your homepage or search engine has changed without your permission
  • Crashes: Programs crash regularly or your computer restarts on its own
  • High disk usage: Your hard drive is constantly busy for no clear reason
  • Strange messages: You get notifications about viruses or that you have to pay to get your files back
  • Missing files: Files have suddenly disappeared or been encrypted

Types of malware

Malware is an umbrella term for malicious software. The main types are:

  • Viruses: Spread by infecting files
  • Trojans: Disguise themselves as legitimate software
  • Spyware: Spies on your activity and steals data
  • Adware: Shows unwanted ads
  • Ransomware: Encrypts your files and demands a ransom
  • Worms: Spread automatically across networks

Step 1: Start in Safe Mode

The first step in removing malware is to boot into Safe Mode. This loads only the most essential parts of Windows, so a lot of malware is not active.

Starting Windows 10 and 11 in Safe Mode

  1. Click the Start button
  2. Click the power icon
  3. Hold down the Shift key and click Restart
  4. Your computer restarts to a blue screen
  5. Click Troubleshoot
  6. Click Advanced options
  7. Click Startup Settings
  8. Click Restart
  9. Press 4 or F4 for Safe Mode, or 5/F5 for Safe Mode with Networking

Choose Safe Mode with Networking if you still need to download updates or software.

Step 2: Delete temporary files

Before you run a scan, it's smart to delete temporary files. This speeds up the scan and can even remove some malware.

Using Disk Cleanup

  1. Type Disk Cleanup in the Windows search bar
  2. Select your main drive (usually C:)
  3. Wait until Windows has analyzed the files
  4. Check all options, especially Temporary files and Temporary Internet Files
  5. Click OK and confirm the deletion

Emptying the Temp folder manually

For a more thorough cleanup:

  1. Press Windows + R
  2. Type %temp% and press Enter
  3. Select all files with Ctrl + A
  4. Press Delete
  5. Skip files that are in use

Step 3: Use antivirus software

Now it's time for the actual scan and removal.

Using Windows Defender

Windows has a built-in antivirus that is quite effective:

  1. Open Windows Security from the search bar
  2. Click Virus & threat protection
  3. Click Scan options
  4. Select Full scan
  5. Click Scan now

This scan can take an hour or longer. Leave your computer alone during the scan.

Using Malwarebytes

For stubborn infections, Malwarebytes is an excellent addition:

  1. Download Malwarebytes from the official website
  2. Install the program
  3. Open Malwarebytes and click Scan
  4. Wait until the scan is complete
  5. Review the results and click Quarantine

Malwarebytes has a free version that works fine for removing existing infections.

Using multiple scanners

No single antivirus detects everything. That's why it's wise to scan with several programs. Good free options besides Malwarebytes are:

  • AdwCleaner (specifically for adware)
  • HitmanPro (cloud-based scanner)
  • Kaspersky Virus Removal Tool
  • ESET Online Scanner

Note: do not install several antivirus programs permanently. Use the extra scanners only for one-off scans.

Step 4: Clean up your browser

Malware often settles into your browser. After the general scan, you should check your browser as well.

Cleaning up Chrome

  1. Open Chrome
  2. Click the three dots at the top right
  3. Go to Settings
  4. Click Reset and clean up on the left
  5. Click Clean up computer
  6. Click Find
  7. Remove any harmful software that is found

To check your extensions:

  1. Type chrome://extensions in the address bar
  2. Review all installed extensions
  3. Remove anything you don't recognize or don't use

Cleaning up Firefox

  1. Open Firefox
  2. Click the three lines at the top right
  3. Click Help and then More troubleshooting information
  4. Click Refresh Firefox
  5. Confirm the action

Cleaning up Edge

  1. Open Edge
  2. Go to Settings
  3. Click Reset settings
  4. Click Restore settings to their default values
  5. Confirm the reset

Step 5: Check startup programs

Malware often adds itself to your startup programs so it starts automatically.

Checking Task Manager

  1. Press Ctrl + Shift + Esc to open Task Manager
  2. Click the Startup tab
  3. Review all programs in the list
  4. Right-click suspicious items and choose Disable

Be careful: only disable what you don't recognize after looking it up.

Step 6: Consider System Restore

If the infection is stubborn, you can try going back to an earlier restore point.

Running System Restore

  1. Type Create a restore point in the search bar
  2. Click System Restore
  3. Click Next
  4. Select a restore point from before the infection
  5. Click Next and then Finish

Your computer restarts and restores system files to the chosen date. Your personal files are kept.

After removal: prevent new infections

Once you have removed the malware, it's crucial to prevent new infections.

Keep everything up to date

  • Install Windows updates as soon as they are available
  • Keep your browser and browser extensions up to date
  • Update other software regularly too

Be careful with downloads

  • Only download from official websites and app stores
  • Be extra careful with free software from unknown sources
  • Scan downloaded files before you open them

Watch out with emails

  • Don't open attachments from unknown senders
  • Don't just click links in emails
  • Be alert to phishing emails that pretend to be well-known companies

Make regular backups

Back up your important files regularly. If you are ever hit by ransomware, you can then restore your files without paying a ransom.

When to call in professional help

Some infections are so serious that you need professional help:

  • Ransomware that has encrypted your files
  • Rootkits buried deep in the system
  • Infections that keep coming back after several attempts
  • If you are not sure what you are doing

In these cases, consider a computer repair service or a complete reinstall of Windows.

Frequently asked questions

Can I remove viruses without antivirus software?

Technically it is possible to remove some malware manually, but this is strongly discouraged. Malware often hides in places that are hard to find, and you may accidentally delete important system files. Always use reliable antivirus software to remove malware safely.

Should I pay if I have ransomware?

Paying the ransom is strongly discouraged. There is no guarantee you'll get your files back, and you are funding criminal organizations. First try to find decryption tools on websites such as No More Ransom. If you have a good backup, you can reinstall your computer and restore your files.

How do I know the malware is really gone?

After the first removal, run another full scan, preferably with a different antivirus program. Monitor your computer for suspicious behavior for a few days. If everything works normally and scans come back clean, the malware has probably been removed. Do stay alert for returning symptoms.

Is free antivirus software good enough?

For most home users, free antivirus software offers enough protection, especially Windows Defender combined with common sense. Paid versions offer extra features such as webcam protection, password managers and VPN, but the basic protection against malware is comparable to free options.

Conclusion

Removing malware can be a challenging job, but with the right approach you can get your computer clean and safe again. Always start in Safe Mode, use several scanning tools and don't forget to clean up your browser. After removal, prevention is essential: keep your system up to date, be careful with downloads and make regular backups. With this knowledge you are well prepared to fight malware effectively.

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