If your computer suddenly behaves strangely, a virus or other malware is one of the first things to rule out. No single sign proves an infection, but two or three together are a good reason to act. Here are the eight signs we see most often, and what to do about them.

8 signs your computer may be infected

  1. Pop-ups and ads everywhere. Ads appearing even when no browser is open, or fake "Your PC is infected, call this number" messages.
  2. The computer became very slow without any change on your side, or the fan runs at full speed while you are doing nothing.
  3. Your browser changed by itself. A new home page, a different search engine or toolbars you never installed.
  4. Programs you did not install. Unknown apps in the Start menu or in Settings > Apps.
  5. Your antivirus is turned off and will not turn back on, or Windows says protection is disabled.
  6. Files are missing or will not open, or have strange new extensions. If you also see a message asking for payment, disconnect from the internet immediately.
  7. Friends receive messages you never sent, or you get password-reset emails you did not request.
  8. Unusual internet activity. The connection is slow even though nobody is using it.

What to do first

  • Disconnect from the internet (unplug the cable or turn off Wi-Fi) if you see a ransom message or suspect someone has access.
  • Do not call phone numbers shown in pop-ups. Real warnings from Windows or your antivirus never ask you to phone anyone.
  • Run a full scan with Microsoft Defender (Windows Security > Virus & threat protection > Scan options > Full scan).
  • From a clean device, change your important passwords (email, bank, social media) and turn on two-step verification.
  • Do not enter passwords on the infected computer until it has been cleaned.
  • Back up your important files to an external drive only if you are sure they are not encrypted or corrupted.

When a full scan is not enough

If the scan finds nothing but the symptoms continue, or the threats come back after removal, the infection may be hiding deeper in the system. In that case, a technician can review startup programs, browser extensions and system files, remove the malware and secure the computer. If the system is badly damaged, a clean Windows installation with a backup of your files is often the most reliable fix.

How to avoid it next time

  • Keep Windows and your browser updated.
  • Download programs only from the official website of the developer.
  • Be careful with email attachments and links, even from people you know.
  • Keep a recent backup of your files.

Need help? ITNova Solutions removes viruses and malware and secures computers for homes and small businesses in Hialeah Gardens and nearby areas. See our Windows and PC optimization service or book an appointment.