Pop ups keep coming

Hi all,
I am experiencing this problem for couple of weeks now. while browsing when I i clink on some thing and new pop up widows comes on top of my browser. I am using google chrome. The pp up window are offers for example saying click here you have won ipad. Also in my browser window on top or right or left or bottom same pop ups appear showing me different advertisements or suggestions then I have to click x to close them. Its really annoying and also on some site like ebay I felt the sites not loading as fast as they were and I an using highest speed available fiber optic brad band. I have tried clearing cookies and pop up blocker is ON too. Any help on this?
regards

Sounds like you might be infected, but for a quick suggestion, try going into chrome settings and extensions and remove anything you haven't installed yourself.