If the hard drive is new, it likely isn't formatted yet. You can format a new drive with these steps:

• Right click on the Start Menu
• Select Disk Management
• Right click on the Unallocated Space
  (If there is no unallocated space, right click on the drive number and select Initialize)
• Select New Simple Volume
• Default settings are typically the best here
• Click through Next and then Finish to complete

Additional information can be found at
https://support.microsoft.com/en-us/help/17418/windows-7-create-format-hard-disk-partition.