Snoopy: You say you have pop-ups disabled, but check if someone didn't define exceptions. It's under options->contents, you have the checkbox for "block pop-ups", and on the same line a button "exceptions", where you can define which sites are allowed pop-ups. I remember there was a malware that filled that "exceptions" part with loads of sites. So even if you get rid of the malware, the exceptions are still there.
(hide) If you only look at some of the discussion boards on a regular basis you can add them to your favourite boards list by going to the Board page and clicking "Add to my favourite boards". (pauloaguia) (show all tips)