gzt:
Ok. Let's have a closer look at that disk. USB interfaces (and windows) can be untrustworthy so...
Plug the drive into an internal sata/ide port, disconnect any other drives, and boot the GParted Live CD. Accept the default GParted boot choices during boot.
Let us know what things look like in GParted, and any information GParted reports about that disk.
Hi there gzt, thanks for your help. I finally got around to installing Gparted and here's what it has to say about the drive:
Cluster accounting failed at xxxxxxx (xxxxxxxx), extra cluster in $bitmap. (there are several of these)
Files system check failed. Totally 144 cluster accounting mismatches.
NTFS is inconsistent, run chkdsk on Windows then reboot it twice.
Unable to read content of this file system and because of this some operations may not be available.
The cause may be missing software package.
The following is required for NTFS support: ntfsprogs.
Yikes ...!