I had a similar prob this morning, wd passport 1 Tb, this might help. Running Win7
The passport was working fine last night, and this morning, nada. Unplugged it and put it back it, it went through looking for drivers and finally came up not working. Nothing in explorer. It did show up in drive manager and on device manager. On device manager, it was showing up under disk drives as “wd bad pcb usb device” and the “wd ses driver” had an error symbol. My other passport was working fine, and came up under disk drives as “wd my passprot 0730 usb device”. Wasn’t a cable prob either as I swapped them around. Drive manager wouldn’t even let me initialise it (note - DON’T choose that option - your data’s still there if you’ve got the same prob I did.)
The problem is the wd ses driver. I plugged the drive into my wife’s computer, which I’d never plugged the drive into before. It did the search for drivers and the drive came up (the little detection window found the drive but couldn’t find the wd ses driver as it’d never been installed on that computer apparently). I updated the firmware on the drive using the wd tool ( http://www.wdc.com/wdproducts/wdsmartwareupdate/?id=wdfMP30_Essential&os=win&fw=1),,) then plugged the drive back into my main computer and it now seems to be working fine.