i have a 100GB iomega portable hard drive that isn't visible when i plug it into the usb port, it gets picked up in the device manages and the balloon in the tray says that it's found the usb mass storage device, it also isn't visible in the disk management anyone have any ideas what the problem could be, have tried multiple computers and different enclosure's and different usb cables, i'm thinking it has to be formatted but because i cant access it i cant do this