According to the second log, it is not finding the drive, which I figured would be the results either way.
With it being an external, I would try a few things.
First, replace the usb cable you are using. If it does not help, you may try pulling the harddrive out of the external casing, and docking it if you have a harddrive dock like http://www.thermaltakeusa.com/products-model.aspx?id=C_00002058
But it is likely that the external just became corrupt, sadly.
Liie I was saying earlier, it can be corrupt if you unplugged it, without removing safely, or it could have been dropped. There are many reasons it can be corrupt.
If the above doesn't work, you can try to recover the disk and repair the bad sectors, but that would require more knowledge of CheckDisk or Disk Part, that I am not experienced enough with to offer.
I would recommend conencting it through Linux distro to see if it connects.. but that is all I can safely suggest from here, as harddrive recovery is not my forte (yet) but file recovery I can help with, if the hard drive itself is a lost cause.