Hardware

Usually hard drives in external enclosures have a seperate power supply. Have you tried taking the hdd out of the enclosure and connecting it directly to the computer? See if that works?

If you do not want to lose the data, certainly do not try to initialize the drive.

Like CG IT stated, you best option at this point is to disassemble the external hard drive case and attempt to connect directly to your computer. The problem you will run into is the fact that it is appears to be a 2.5" hard drive case (guessing from the model you gave). You will likely need some adapter to plug it into a workstation...

If the data is super important, take it to a data recovery place.

Do you have anything else plugged into your machine, or maybe did you assign the drive letter to another network drive? Sometimes Windows will not pick the next available drive letter and want to assign the same letter to external drives (such as G:). If G: was assigned to a network drive then windows will not assign anything to the external drive.

{1}

Try rebooting the computer without any USB devices attached. Then plug in the USB drive, right click on My Computer, select manage, and then click ?Disk Management.? If the drive is not present in the Disk Management window or if you are not able to access it, then the drive may have failed. In this window you should see all of your connected physical drives, their format, if they are healthy, and the drive letter.

Change the drive letter of the drive. Right-click on the drive in the list, and from the resulting menu select "Change Drive Letters and Paths"

Click on Change so you can change the drive letter. Click Change. Select a new drive letter from the drop down list, preferably the one that is not normally used for this drive.

Click Yes on the confirmation screen and you are done.

{2}

Write down all fixed Disk and CD/DVD drive letters so as not to delete them. DO NOT delete any of the fixed hard disk drives or CD/DVD optical drives registry values.

1. Login with Administrative privileges.

2. Disconnect all USB or FireWire storage devices.

3. Open Registry Editor by typing regedt32 in the Run box and navigate to the following registry key: HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices. Right click on MountedDevices and select Export. Save this file as you may need it in case something goes wrong. Save it as Devices.reg, it should default to My Documents.

4. Under HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices there will be registry keys with the name that resembles the format of \DosDevice\X: where X can be any alphabet letter which corresponding to your physical system drive letter.

5. Delete all possible USB drives, FireWire drives and external drives which have a drive letter.

<b>DO NOT delete any of the fixed Hard Disk Drives or CD/DVD optical drives registry values.</b>

Exclude \DosDevice\A: which normally reserved for floppy disk drives.

The USB specification for a USB port is 500mA per port. If a device needs more then 500mA, the USB port may be switched off by the over current circuit.

To avoid too high a power consumption on the used USB port, connect the External USB device to a second USB port with the additional Power cable . This provides up to 1000mA to the USB device. If the device still fails, try a self-powered USB Hub, as they are, in most cases, able to provide more than 500mA per USB port.