Second SATA Drive Not Visible in Vista 64

Hi
I have Vista 64 running on my PC. I recently added an additional 1TB Sata Hard Drive to my system for backup/storage but it does not show in Vista when opening the (My) Computer section. Cameras, USB Drives, Phones etc all show up instantly without issue.

The original HDD has Vista 64 on it is also a SATA drive.
Both drives are Seagate Barracuda.
The 1Tb drive shows up during boot and is available through the Device Manager so it is plugged in OK

They show as:
ST310005 28AS SCSI Disc Drive (The new HDD)
ST340083 28AS SCSI Disc Drive (Original with Vista 64 installed)

When I 'populate the volume' in device properties the new drive shows as:

Disk: Disk 0
Type : Unknown
Status: Not Initialised:
Partition style: Not Applicable
Capacity: 953870 MB

All other device drivers are apparently working with no conflicts.

Any ideas how to get the drive to work/show up please?
Thanks.