are you sure its not your connection? if you are on a notebook are you able to test it on someone elses internet connection, if you are on a desktop, can you try connecting to the internet through your mobile?

i know that when i go over the monthly download limit my home internet gets speed limited, and i cannot use msn because the connection is too slow so msn wont connect... i use pidgin though and although that isnt trouble free, it eventually connects...