That link may be problematic because it has an imbedded link to the direct download. In the future, try the link I used above. I had also PMed Justin about Easeus and he OKed the link I am using. In the process, Justin explained that direct links to downloads were an issue.
At any rate Futs has already formatted the partition so I am not sure what would happen if that program were run now. My original thoughts were that the partition table was corrupted.
If the drive was removed while it was being written to, that would explain the corruption.
Futs, now that you have recovered all the files you can find you might want to try Easeus partition recovery or testdisk on the partition.
Both of these utilities rely on some input from the user. For instance, if you had several partitions originally you need to reconstruct them in the same order and size as before.
If your entire drive was one large partition then that makes it fairly simple. You still need to know if the drive was FAT32 or NTFS. Also, if NTFS were you using the default cluster size or something else.
You should always use the safely remove icon in the tray. If you don't have that option then you have the drive setup as if it were an internal drive. That makes for faster transfer but places the data at risk if a write cycle is interrupted.