Most av software flashes up a warning if you receive a dodgy email or go to a dangerous site.
Have you used malwarebytes before. The reason I ask this is because you may not be fully aware of how Malwarebytes works. Infections of any kind can be made up of many segments , if you clicked on anything it found before quarantining and deleting you might have seen it say something like joe bloggs pup 5 , this means that joe bloggs pup is made up of 5 segments.
This is the important bit.... Malwarebytes is one of the best programs around but it cant always get rid of all segments of something on the first scan/quarantine/delete. You must do repeated scans till it finds nothing.
Also try adwcleaner by the same company
WARNING .. be careful when typing the malwarebytes name into a browser their is a rouge site called malawarebytes , spot the extra a in the name