Browser keeps showing notifications or fake virus alerts

A website may be sending unwanted notifications; an alert in a browser does not prove infection.

Stop if unsure or if a new warning appears. Save your work before changes and ask IT before changing a work device. Never disclose passwords or recovery keys.

Do not click the alert, call its number or install anything it offers. Close the affected tab.
Open browser settings and search for Notifications. Remove or block unfamiliar websites from the allowed list.
Check browser extensions and remove only those you can identify as unwanted. Open Windows Security from the Start menu, not the alert, and run a scan there.
If you entered credentials, paid or allowed remote access, disconnect that remote session and seek qualified help. Change affected passwords from a safe device and contact your bank if relevant.

Related guide: Program does not start

Test after each step and stop when the issue is solved. Checkmarks are not permanently saved.