Windows 7: Hard Drive missing

I currently have three Seagate Barracudas 7200.11 1.5 TB drives in my system for media storage.

I just added a Hitachi Deskstar 2 TB drive.

Once I added the Deskstar one of my Seagate drives disappeared from Windows.

I have a WD 500 gig setup as my bootdrive
I have a Seagate 1.5 setup as my D: drive (this is the one that's showing failed in disk management)
I have the other two Seagates and the Hitachi drive setup as E: and as a spanned dynamic drive.



I have run SeaTools on the three Seagate drives and they all test as fine. They are all showing up in the BIOS too.

Any ideas?

Can post a screenshot of Disk Management.

http://www.sevenforums.com/tutorials...en-forums.html

Go to the following:

• My computer
• Right click management
• In the new window go halfway down and you will see Drives
• Double click on drives and on the lower part of the screen you will see the drives listed (see attached image)

Here you go.

The missing drive has not been allocated nor has it been assigned a letter, are you able to perform these functions?

Only options I get are: Reactivate Volume or Delete Volume

or use diskpart command:
start - Run: cmd
diskpart
list disk
Post the result screen

Screenshot

Reactivate volume.

Tried that and nothing happened.