I used on for the trial run called Popzilla. It worked well, I don't remember the price.

Adsgone there is no better take it from a computer guru

rouxsterre-I searched for the program, but I wasn't able to find it.

David-although, I do run adaware frequently (and am amazed by what it routinly finds) it only slows these popups, it can't kill them. I also run spybot. The two programs seem to need to run in order to kill everything.

I just installed a free pop-up killer at the office, but don't remember the name. Do a search at www.pcworld.com - lots of good software on that site.

See post #6. It kills everything (in my experience). The only thing it would not kill is an installed adware PROGRAM (see post #8).
The good thing about the popup killer in #6 is that to view BoatTrader ads, you just hold down the Ctrl key and click on the picture. Voila!
I can email it to you, if you would like. It's tiny (like 10k).

One more thing - can you capture a screenshot of the 'blackmail' ad?
When you see the ad, press the 'PrtScrn' key to capture the entire window, or Alt + PrtScrn to capture only the active window (the popup), then open Paint, and choose 'Paste' from the right-click context menu.
Save the file as a jpeg, and attach into your next post.

Actually, just as I was scrolling down to this post, the little bugger came back up. I had run the two scanning programs and they had killed it for about 24 hours.

I just reran spybot, this is what it found.

I also reran Ad-aware. Here the files that it found. Now that the pop-up window has restablished it's self, they are comming about every 3-4 minutes.

Holy cow! When I want to post a big picture I get thumbnails, now that I don't need one, there huge!

BTW-there are several different pop up windows. That looks like the one that points to the originator. The other windows are more advertisments hawking different wares. The all use the same format though.