The owner had used some third party tool to create partitions. We tried another drive where I showed how FDISK and FORMAT was used to create the same partitions. It survived the move to the USB case. I don't know of a good fix except to put the drive back as booting then copy the files off somewhere else with a properly prepared drive then start again fresh on that drive once your files are safe.
I was running a desktop with a maxtor 120 GB HD under win 98. It's got 5 partitions on it with data on each partition. I purchased a USB external case and installed the drive into it. When I plug the USB cable for this external hard drive case into my XP Media Center Edition desktop, it recognizes the Mass Storage Device, but doesn't bring up/recognize any of the partitions/drives. I thought this should be plug and play ... what's wrong?