Think You Have a Virus? How to Tell — and What to Do First

Not every misbehaving computer is infected — but some are, and the order you do things in matters. Here is the safe sequence.

The real warning signs

Browser home page changed by itself. Pop-ups appearing outside the browser. A new "antivirus" you never installed demanding payment. Friends getting emails you did not send. The fan roaring while you are doing nothing. Any of these: treat it as infected.

1. Disconnect, do not panic-click

Turn off Wi-Fi or unplug the network cable. Malware often needs the internet to do damage. Whatever you do, never call a phone number a pop-up shows you, and never let a "support agent" from such a pop-up connect to the machine — that is the scam itself.

2. Run the scanner you already own

Windows Security (built into Windows 10 and 11) is genuinely good. Run a FULL scan, not a quick one. Let it quarantine what it finds, then restart and run it again until clean.

3. Change passwords — from a different device

If anything was found, assume typed passwords were seen. Use your phone (on cellular, not the house Wi-Fi if a router hack is suspected) to change email and banking passwords first.

4. What NOT to do

Do not install three more "cleaner" apps from ads — most are junk or worse. Do not pay any pop-up demanding money. And do not keep using a machine for banking until you are confident it is clean.