Since last week, when use ubunt, my firefox browser pop ups some scammy article links up left corner as it is shown in the image. So does that mean my computer is infected. And if it does, then how can I clean it? I used ClamTK, but it didnt find anyting.
You can disable all push notification in Mozilla Firefox via the main menu
Edit->Preferences->Content then by
Notifications click on
Choose button to change settings of every site that sends you push notifications.
You don't have to install any add-ons or modify any file on your OS.
For further information about Push Notifications in Mozilla Firefox: