In the interests of trying to help you:-
Assuming XP Sp2/3
Internet Explorer.
Have you tried
How to configure the Pop-up Blocker on a computer that is running Windows XP Service Pack 2 ?
For Firefox, read
https://support.mozilla.org/en-US/questions/926777
I take it you do mean 'pop-up blocker' and not just 'ad blocker'?
Last edited by BOAC; 16th July 2013 at 11:46.