@edgarblythe,
I've been getting annoying popups on my screen too, so I downloaded two free popup blockers, and they seem to be working pretty good. The first one is AdBlock (they request a donation), and the second one is Popup Blocker. After you download these programs, they count the number of popups they block, and according to the two, the Popup Blocker blocks more popups than AdBlock.
You can also block any popups by clicking on AdBlock to stop any one from popping up.