How to reset HD to its original factory settings

How can I reset my HD to its factory settings? I forgot to format the HD before I loaded USB with a Windows Restore File. Now my HD shows that it has 2TB available and not the full 12TB.

Hello, nonconcrete

Well, if you have just restored the Windows OS on the internal harddrive without assigning the drive letter to another drive then assign the drive letter to the unallocated drive using disk management.
Open the disk management using the diskmgmt.msc and then you can see the unallocated partitions on the drive with black color bar.
You can follow the instructions that are mention on the link given below.

If you face any issue then you should try contacting WD’s Technical Support about this for live assistance and troubleshooting

To Contact WD for Technical Support

http://support.wdc.com/support/case.aspx?lang=en

The link below will allow you to call support