This is a link to the free version of pop up stopper.  http://www.download.com/Pop-Up-Stopper-Free-Edition/3000-7786_4-10048866.html

I have used that program for many years, then noticed there was a function of IE 6 that also stopped pop ups.

I never had any problem with pop up stopper, except for the times I have to turn it off to get a pop up that I need.

I hate pop ups!  I use them only when I am forced to do so, have often not bought something just because I have to use a pop up to look at it.