Yes I was wrong.I know, it's NB. So it's not surprising, I clearly mentioned I've tried uninstalling the browser, and ad block, tried forcefully blocking the ad. Didn't help. But I found the solution. It was express install, probably made it into my PC via daemon tools so thanks a lot for helping. The ads are gone, oddly enough it was only effecting NB. Lol.
It's not a virus.