Help with wd hd my passport plz!

i have external hd my passport it was working good with me but now when i connect it with my computer my computer go slow and sometimes dont respond when i remove the hardisk its work back normal but when i connect it and wait mayby 30 minutes its work finally but when i try to copy file from from the hd to computer its only prepare to copy then go and nothing happen and its prepare very slow then it dosent copy anything plz i need help!! i tryed to scan it nothing happen and i tryed to disk check !

your drive is failing, most likely heads