I’ve noticed that there seems to be more than usual problems when using between XP and Vista and Windows 7. Something is apparently corrupt I saw these posts http://community.wdc.com/t5/My-Passport-for-PC/How-to-eliminate-potential-problems-on-USB-Powered-Drives-and/td-p/118262 and http://community.wdc.com/t5/My-Passport-for-PC/System-will-not-read-this-Hard-Drive/m-p/117846#M3739 post 8
Joe