A browser notification is a message sent by a website after you granted it permission. A deceptive site can make one look like a system-virus alert, a delivery warning or a support request. It may appear even after you close that site's tab.
A useful example
A corner alert says "five viruses found" and names a website under the message. Do not call the number or open its cleanup link. Open your browser settings directly and revoke that site's notification permission. If you only viewed the alert, you generally have a permission problem; if you installed software, investigate the installation separately.
The practical distinction
A real Windows Security detection can be reviewed inside Windows Security's Protection history. A website's alert is not the same record. Chrome's
site-notification settings let you identify and block senders. If alerts persist, check for another allowed site, extension or installed app rather than assuming the first change failed.
Practical distinction
Identify the sender by its site name before revoking permission. If a real security app also reports a detection, handle that separate record inside the app.
