Following on a hint from one of the articles linked to above, I found WebWasher. It's a free program that has all but eliminated popups; I'm very impressed so far.

I also highly recommend AdAware, to remove whatever spyware, data miners, and other nefarious bits that have been engrafted onto your system by those "nasty, unscrupulous modifiers." (Ten point bonus if you know the source of that last phrase.) And even if you were on the stick and got AdAware a while ago, it's a good idea to download the latest: version 6 uncovered several dozen of the buggers that version 4 didn't know about.

Aloha,
Mark

PS, unfortunately, the AdAware link doesn't work well on older browsers. I had to use IE 6.0 to see it. And be careful: the company is in Germany: their website is "lavasoft.de", not "lavasoft.com"...although the latter site is nice enough to provide a link to the AdAware one.