Passport essential doesn't works with windows seven 64 bits


my passport doesn’t works on windows seven 64 bits;

the led is power on the passport when i plug it in the PC (last new dell inspiron xps 9100) but the hard drive dosesn’t start. ( i use the usb cable sell with the passport)

it works well on xp and seven 32 bits.

my webcam, mouse keyboard works well too.

seven doesn’t recocgnize the hard drive.

how i can resolve this problem ?

thanks in advance