I need some help

I often run the scan on my laptop to be sure I have no issues. Well lately when I go to open a link I have had a tab open with what looked like a newspaper but a smaller pic would come over the top of it with an ad for Fast and Furious. Running the scan did not stop it from happening. Today when I clicked on a link on a page I have used for years and its not always the same one I get this

I have run the scan several times but nothing seems to be stopping it. I am not overtly computer literate so anyone that can give me some advice would be grateful

Scanning does not seem to be stopping