I have a Passport external HD convected via USB to my intel iMac. Yesterday, while I was backing up some files to the cloud (Zipcloud) I got a message saying to eject my external drive. I was in the middle of something and by the time I got to it, the external icon had disappeared. I unplugged and then re-plugged, but the HD is not recognized by Disk Utility or under USB in System profiles. I tried the HD on my macbook pro running Lion but it doesn't recognize it either. I can feel the drive spinning but I'm unable to access it to make changes or attempt repair. It was running fine before I got the message to eject. Any suggestions?