Try to use 'system restore' to put your computer back to a time before you think you got the dialer problem , or you could try usin' a programme like 'A Squared' , or 'Sophos' (if you can download them) ....... think they shift most dialers ......... or just type 'dialer removers' into your computer to see if there are any similar programs that you could use ....... you could even search around the 'net' for a dialer 'tool' that should erase it from your computer.
You have to be very careful with dialers , as once installed they can run your bill up by callin' premium rate numbers without your knowledge each time you boot up.
But most of all , be a bit fussier about which porn sites you visit ....... that's usually the most likely place to pick up all sorts of dialers!
I used to have Norton , but i didn't find it much 'kop' to be honest , i was still left with a lot of crap to get rid off manually , an' you're probably just as well off with the likes of the free AVG ......... or if you prefer to pay for one 'Kaperskys' is supposed to be unbeatable.