Thanks Nathan!
1. Is there no chance, that MalwarebytesApp solves my problem, by scanning my cellphone and clearing/deleting the infected areas?
2. the following browsers are installed: Firefox, Chrome, Startpage. I cannot delete Chrome, but I could deactivate it. Popups still come... Where, at Firefox, I can find the infection? There's no suspicious AddOn.
3. How do I disable Javascript on an Android7 system? But this action surely will cause side effects on other apps, right?
4. Android's back key - what's that? How can I clear the history and cache? (I already did restart of android, as well as switch on/off)
I'm not a rookie, but surely not so familiar with Android7 system. I'm really happy about more detailed information, e.g. step-by-step instruction how to find and delete the infection.
Thanks a lot
Best regards!
Woita