this may or may not help you but its my best guess.
try clicking start.run and type msconfig,click ok.
click the start up tab and untick everything except your antivirus and firewall and restart the computer.
as the computer restarts keep tapping F5 or f8 and select safe mode from the list of choices.
when in safe mode click start/search or find and type the name of the dialer(eg/ "sexnow") into the box and delete all that is found.empty your recycle bin.
the registry may also have an entry somewhere.
back it up first just in case,click start/run and type regedit,click ok.
click my computer,file/export and save it somewhere handy(restore the reg by clicking on the saved file)
once backed up click edit/find and type the name of the dialer into the box and it will search the registry,stopping on anything it finds.right click it and select delete.DO NOT DELETE ANYTHING ELSE.
tap f3 and it will continue searching again.keep doing this untill it says finished searching.restart the computer.
hope this helps.