malware on chrome

Hi all I am very new to mac and have a macbook air.

So I have Chrome on it with adblock plus and until recently, I had no problem until i start having random ad on it by "ishopless" that are really annoying as well as pop up.

I uninstalled chrome and adblock plus and installed them again, same problem.

Some told me I have a malware, but I haven't downloaded mac defender (or any stuff like that), despite having seen the website poping up several time. I only downloaded vlc, chrome and bittorrent, could it be it?

thanks for your help! i

- sorry for the mistake, I am french, as well, I wasn't sure where to post this, please feel free to move the thread and sorry for this