vista wont show my buffalo ext hard drive

hi
ive recently bought a cx500u2 buffalo external hard drive but when i connect it to my pc running vista it goes non responding when i go into my computer or into disk management. i tried it on my laptop running xp and it works fine im at the end of my tether with this plz help

 

Well i went to the discontinued list of products and mines was there but it dosnt let me enter my serial number to be able to download anything:cry. Do you definently reckon that what i need to do (get the download somehow)?