Popup adverts: Vista laptop

[Zog]

Hi All,
My laptop recently started playing up, such that I now get popup ads appearing all the time, plus my standard browser, Google Chrome, has been replaced by Yahoo, which is driving me mad. I run Norton anti-virus and have tried all of the clean-up processes, plus restored to an earlier system setting, all to no avail. Any ideas please? I've also tried searching in both internet settings and Google Chrome settings for whatever it is that re-directs my first browsing page to Yahoo, but can't find any clues.
That'll teach me to look for torrent websites!
All help gratefully received.

 

[crispy duck]

i use ABP addon on firefox and that keeps all the banners and pops ups off my laptop. also check in your programs list see if there is a toolbar u can remove as sometimes you install things by not reading the text and just clicking next on installs. I also use a program called malware bytes which is free and gets rid of pop ups and crap.