I do have another 1TB external HD as a backup but it's full. (I need to delete some old backups off of it.)
The WD HD is a My Book Essentials, not the passport. It has its own power source.
When I plug it into the USB port I get absolutely nothing. There are no dings, no clicks, and no notice of external media. Its as if it wasn't there.
I don't know if the HD is on the verge of failure or what. I didn't have any trouble with it prior to running the defraggler.
I've used defraggler before and it has worked wonderfully, without issues, so I don't know if it was something the defraggler did or simply identified.