2nd hdd not recongnized - IBM Lenovo ThinkPad T400s Notebook - Core 2 Duo SP9400 2.4GHz - 14.1" - Black (2808DHU)

Safest is way to install a removable drive tray such as Welland EZStor ME-751 Trayless HDD Rack 5.25" Bay for 3.5" SATA HDD/SSD - Anti-Shock, Scratch-Proof.
Then you can swap HDD anytime.
You can also install new (now upgrade) Windows 8.1 on a 2nd HDD internally. But sometimes the 2nd OS can damage the first OS if ou are not careful with C: drive letter.

same thing happened to my hdd I ran this test http://www.hgst.com/support/downloads/ and it fixed it hope it works

Hi ,
It sounds like you need to format the harddrive , then you will be able to use it .......
if you need more help , let me know .................Roy

No need for software. The standard hard drive size is 10GB. I don't remember the exact limit but the machine will only recongnize a certain amount so it will do you any good to buy a larger capacity drive. Just get the smallest/cheapest one and you'll be fine. These take the smaller "laptop" size drive in case you did not know. Other than that just install the new drive and let the machine do the setup. If your old drive failed then keep in mind you will have lost any document server files, scan destination or fax destination info and will have to re-enter that info.
Good Luck

I support the suggestion posted by Joed911. This is the best way to connect the 2nd HDD.

Have a look for the drive in "Device Manager" (control panel -> system -> hardware tab) and see if it is there.
If it is, go to the "volumes" tab and press the "populate" button.

Jump? Ha! Never heard that term. How about boot?
Nowadays people just load drives as Cable Select; it should have worked with the old drive set to Master, but try to set them both to that and try again, or boot to a LiveCD or the drive utility disk so you can configure them on that. If they don't appear correctly in the BIOS, just double-check that power and data cables go to each drive, etc. You may need to follow the BIOS instructions or enter the BIOS controls by hitting DEL or F10 on powering up until the menu appears; then you can select the drive to try to boot first, etc. and save your settings.

check if battery is dead.
check if the device is recongnized by computer as a USB MASS STORAGE.

and perform a Firmware Upgarde.

check the utility in ur device Support Page.

both hard drives will need to be jumpered to a master and a slave or both have to be jumpered to cable select. normally the jumper setting are either on the label of the drives or are marked on the bottom of the drives near the jumper drives. if the setting are not shown find the drive type, model and capacity then do a google search for the drive "select the factory manufacture link" and search their site for the jumper setting of the type drive you have.
BPCS

this is os problem
reinstll or repair os
or

harddisk problm