Ubuntu 14.04 cannot mount/recognize NTFS HDD

Question

I connected an HDD to the USB drive using a docking station.
I think the HDD is using NTFS, because it has Windows 7 installed.

Before connected the HDD:

ls /dev/ | grep sd

output was:

sda
sda1
sda2
sda3

After I connected the HDD:

ls /dev/ | grep sd

the output was:

sda
sda1
sda2
sda3
sdb

So sdb was recognized.
And this is the output of:

sudo fdisk -l

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168            
sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0xf620db8e

Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1  1953525167   976762583+  ee  GPT
Partition 1 does not start on physical sector boundary.

Here's an image of a screenshot of Ubuntu's Disk utility

where you can see that the disk is recognized but not mounted.
Or maybe it's corrupt.