Sometimes you will see pop ups if they come through a "local intranet" or are labeled as "trusted sites." Also, some windows with animated content are not blocked.
Goto Tools > Pop Up Blocker > Pop Up Blocker Settings. At the bottom is a FAQ link. Click on this and you will see a myriad of solutions.
Take care, Gregory david Stempel FIREFRAMEi m a g i n g www.americanphotojournalist.com www.soundexposure.org