How to Tell If Your PC Has a Virus — And What to Do

Most infections are silent. By the time you notice something is wrong, the malware has often been running for weeks.

Warning Signs of Infection

Performance signs:

  • PC is suddenly very slow for no reason
  • High CPU or RAM usage even when idle (check Task Manager)
  • Fan running loud constantly

Behaviour signs:

  • Browser homepage changed without you doing it
  • New toolbars or extensions you didn’t install
  • Ads appearing on websites that didn’t have them before
  • Programs opening or closing on their own

Security signs:

  • Antivirus disabled and won’t turn back on
  • Windows Defender or Firewall turned off
  • Accounts getting suspicious login alerts

What NOT to Do

  • Do not pay any “support” popups — these are scams, not real Microsoft alerts
  • Do not call numbers shown on screen — legitimate companies don’t show phone numbers in virus alerts
  • Do not run random “removal tools” you find from a Google search — many are malware themselves
  • Do not format immediately — data recovery becomes harder and it may not even be necessary

Correct Removal Steps

Step 1 — Disconnect from the Internet

Unplug the ethernet cable or turn off WiFi. This stops the malware from sending your data out or downloading more.

Step 2 — Boot into Safe Mode

  1. Hold Shift and click Restart from the Start menu
  2. Go to Troubleshoot → Advanced Options → Startup Settings → Restart
  3. Press 4 to boot in Safe Mode

Most malware cannot run in Safe Mode, making it easier to remove.

Step 3 — Run Windows Defender Full Scan

  1. Open Windows Security from Start
  2. Click Virus & threat protection
  3. Click Scan options → choose Full scan
  4. Click Scan now and wait — this takes 30–60 minutes

Step 4 — Run Malwarebytes (Free)

Windows Defender misses some things that Malwarebytes catches.

  1. Download Malwarebytes Free from malwarebytes.com (on a clean device, transfer via USB)
  2. Install and run a full scan
  3. Remove everything it finds
  4. Restart normally

Step 5 — Change Passwords

After cleanup, change passwords for:

  • Email accounts
  • Banking apps
  • Any account you logged into on the infected PC

Do this from a different device if possible.

If the Infection Is Severe

Some ransomware and rootkits cannot be removed without a clean Windows reinstall. Signs it’s too deep:

  • Ransom note or files encrypted
  • System won’t boot properly even in Safe Mode
  • Antivirus completely uninstalled/blocked

In these cases, bring it in. We handle full virus removal, data rescue, and clean reinstalls.

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