WD Elements 2TB External hard drive BLINKING LIGHT Problem

hi… i just got my external hard drive and everything connects e.g my usb cord and my ac adaptor … but when this is all pluged in my light blinks and thats all that happends … i have tried some stuff such as … trouble shooting and the disk manager steps but none of this works… on the disk manager my external hard drive does not show up even though its pluged in … im really cconfused… could anyone help… btw im using windows 7 and its compatible with it !!! if you have solved this question could you reply … help me !!!

thanks …