Antivirus & Security

Signs Your Computer May Be Hacked — and What to Do

Unusual slowness, strange pop-ups, or accounts you don't recognise? Learn the real warning signs that something may be wrong — and the calm, practical steps to take.

Signs Your Computer May Be Hacked — and What to Do
Photo: FlyD · Unsplash

Most people picture a dramatic Hollywood moment when they think of being hacked. In reality, the signs are usually quieter — and easier to miss. Here's what to actually look for, and what to do if you spot it.

Common Warning Signs

Your computer is behaving strangely

  • Much slower than usual, even after a restart
  • Programs opening or closing on their own
  • Your cursor moves when you're not touching the mouse
  • Your webcam light comes on unexpectedly
  • Unfamiliar programs appear in your app list or taskbar

Something looks off with your accounts

  • Password reset emails you didn't request
  • Login notifications from unfamiliar locations or devices
  • Contacts saying they received strange messages from you
  • Purchases or account activity you don't recognise

Your browser is acting odd

  • Homepage or search engine changed without your permission
  • New toolbars or extensions you didn't install
  • Constant redirects to sites you weren't trying to visit
Important: A pop-up on a website claiming your computer is infected is almost certainly a scam, not a real warning. Real security alerts come from Windows Security (the shield icon in your taskbar) — not from a webpage or a phone call.

What to Do If You're Concerned

  1. Don't panic. Many of these signs have innocent explanations. Work through the steps calmly.
  2. Run a Windows Security scan. Open Windows Security from the Start menu, go to Virus & threat protection, and run a Full scan. It's free and built into Windows.
  3. Change your most important passwords — especially email, bank, and any account you use to log into others. Do this from a different device if you suspect your computer is seriously compromised.
  4. Check for unfamiliar programs. Go to Settings > Apps > Installed apps and sort by install date. Remove anything you don't recognise.
  5. Review browser extensions. In Chrome, go to the three-dot menu > Extensions. In Edge, go to Extensions from the menu. Remove anything unfamiliar.
  6. Enable two-factor authentication on your key accounts so a stolen password alone can't get someone in.
  7. Keep Windows updated. Go to Settings > Windows Update and check for updates.

If scans come back clean and your accounts look normal, you may have had a software glitch rather than a real intrusion. If you're still worried, ask us and we'll help you dig deeper.

Frequently asked questions

A website is showing a pop-up saying my computer is infected. Is it hacked?

Almost certainly not. Websites cannot scan your computer — that pop-up is a scare tactic designed to get you to call a fake support number or download something harmful. Close the tab. If it won't close, press <kbd>Ctrl</kbd>+<kbd>W</kbd> or use Task Manager to end the browser. Real security warnings appear in the Windows Security app, not on a webpage.

My computer is slow. Does that mean it's hacked?

Not necessarily. Slowness is most commonly caused by too many programs running at startup, a full hard drive, or Windows running updates in the background. Run a Windows Security scan to rule out malware, then check your startup programs in Task Manager (<kbd>Ctrl</kbd>+<kbd>Shift</kbd>+<kbd>Esc</kbd> &gt; Startup apps) and disable anything you don't need.

Daniel Nguyen

Technical writer focused on everyday troubleshooting — error messages, email setup and software installs in plain English.

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