Technical Coach said:@Dan
Just reinstalled Adobe Flash Player(to watch videos from the MWSE site) and this seems either the trigger or part of the problem(flash related on Mozilla) as the pop ups came back the next visit to Silvertails.
Uninstalled and the problem goes away.
While using adwcleaner i don't have the option to tick removal for each extension so i assume it is the default setting so i hit clean but it never cleans the two issues it finds.
Manually i can delete both issues, a rescan shows the issue is gone after deleting manually.
Here are the two issues it finds in Mozilla and they only reappeared after reinstalling Adobe Flash Player.
C:\Users\Me\AppData\Roaming\Mozilla\Firefox\Profiles\9sto0jkt.default\prefs.js ]
C:\Users\Surfing Account\AppData\Roaming\Mozilla\Firefox\Profiles\0y34eycj.default-1403254580958\prefs.js ]
"Surfing account" is the guest account and "Me" is administrator---- i do not surf the web using the Admin "Me" account so the entry in this area only occurred after allowing Admin rights while installing Adobe Flash Player.
AFAIK these can still get I'm even with guest account the sneak in somewhat like a cookie gets inserted. The nature of the internet or browsers is that it downloads cookies, images and JS to your computer through natural browsing and this opens a door for these to be inserted.
Although they are going into APPDATA there is going to be another place somewhere on your computer that is holding the payload