Is your PC slow, acting strangely, or opening windows on its own? It might be infected. Here are the signs to recognize and the actions to take immediately.
The most common infection signs
- The PC is much slower than usual
- Pop-up ads appear even without browsing
- The browser opens by itself or changes homepage
- Programs install themselves
- You receive strange error messages or payment requests (ransomware)
- The fans are always at maximum, even when idle
- You can no longer install or update antivirus
1. Check with Windows Security
Open the Start menu and search for “Windows Security”. Run a full scan. If threats are found, follow the instructions to remove them.
2. Install Malwarebytes
Malwarebytes is a free software very effective against adware, trojans and hidden malware. Download it, run a scan, and remove detected threats.
3. Check running programs
Open Task Manager and check if there are processes with strange names or that consume a lot of CPU or RAM without reason. If in doubt, search the name on Google or on sites like Should I Block It.
4. Check recently installed programs
Go to Settings > Apps > Installed apps and sort by “Most recent”. If you see software you never installed, uninstall it.
5. Scan the PC in safe mode
Some viruses hide during normal startup. Restart the PC in safe mode with networking and run a full scan with Malwarebytes or Windows Defender.
6. Reset the browser
If the browser opens by itself or is full of suspicious extensions, reset it:
- Chrome: Settings > Reset and clean up > Restore settings to their original defaults
- Firefox: Menu > Help > Troubleshooting Mode > Refresh
- Edge: Settings > Reset settings
7. Change important passwords
If you suspect a compromise, immediately change the passwords of your main accounts (email, social, online banking), preferably from another secure device.
8. Keep the system updated
An updated system is less vulnerable. Go to Settings > Windows Update and install any available updates.
When to consult a technician
If the PC continues to behave abnormally despite scans, or if you fear sensitive data has been stolen, consult a technician or consider a system restore with backup.
Conclusion
Recognizing an infected PC is essential to intervene in time and protect your data. With the methods described in this guide you can perform a thorough check and act independently. All you need are a few free tools and a bit of attention.










