Popup blocker failing?

Have bt-yahoo homepage. windows 7 explorer9. McAfee net-protect says all ok no virus. windows updates are current as is net-protect. Persistant Unilever popup adverts flicker even with popup blocker set to max. Only started when updated yahoo this week. giving us a headache with flickering Other popups blocked on most pages, but some still get through. How can we stop this other than getting a new homepage? Thanks.