I've also noticed this sudden barrage of low-brow Vimax ads. I believe that in my case, my computer has been infected with clicksor, among other viruses. I went out of my way to buy a full copy of Norton, but it has since not detected nor resolved the problem.
I think the only real solution will be a full wipe/re-install of my Windows image.
Sorry to be the bearer or bad news.
Bad form on Norton's part to be unable to correct this problem!
