How to know if you have a virus

Viruses and other malware don't always announce themselves. Sometimes the only clue is that something feels off. Here are the most common signs and what to do about them.

Unexpected slowdowns

If your PC or laptop has gotten noticeably slower for no obvious reason (same programs, same habits), malware could be running in the background. That said, slowdowns can also be caused by too many startup programs, a full disk, or aging hardware. Run a full scan with Windows Defender or another reputable antivirus first; if the slowdown persists after a clean scan, consider a professional check.

Pop-ups and fake warnings

Constant pop-ups, especially ones that say "Your PC is infected" or "Call this number to fix your computer," are a strong sign of adware or a scam. Legitimate security software doesn't work that way. Don't click the pop-up or call the number. Close the window, run a real antivirus scan, and if pop-ups keep coming back, get help from a technician who can remove the underlying software.

Browser redirects or new toolbars

If your browser opens pages you didn't choose, your homepage changed, or you see new toolbars or extensions you didn't install, something has modified your browser. That's often adware or a browser hijacker. Resetting the browser and removing suspicious extensions can help; stubborn cases may need manual cleanup by a pro.

Strange behavior: files missing, crashes, or high network use

Files or folders disappearing, programs crashing more than usual, or the computer acting on its own (e.g. mouse moving, apps opening) can indicate malware. So can unexplained heavy network or disk activity when you're not doing much. If you see any of this, stop online banking and sensitive tasks until the machine is cleaned. Back up important files to an external drive if you can do it safely, then get a full scan or professional removal.

Ransomware: locked files or a ransom message

If you can't open your files and see a message demanding payment to unlock them, that's ransomware. Don't pay unless you've exhausted other options and a professional advises it. Turn off the PC to limit damage, don't reconnect backup drives that might not be infected yet, and contact an IT professional. Recovery depends on backups and the specific strain; a pro can assess your situation.

What to do next

Run a full scan with Windows Defender or a trusted antivirus. Remove any threats it finds and restart. If problems continue, you're not sure what to trust, or you think you might have ransomware, get professional virus removal. A technician can clean the system, restore from backup if needed, and help you harden security so it's less likely to happen again.