I'm having similar problems, and I have a popup blocker but there is something on my PC that I can't find that is causing popups, but it loads them from my PC so they don't show as popups and thus my blocker doesnt work on them.

I've used AVG, AdAware, Spybot Search & Destroy and Spyhunter to try to find whatever it is but nothing works. I'm going to re-format soon I think, but I can't find the discs, lol