What Is Wrong With My External HDD?

I have a problem with one of my external HDDs. My computer does NOT recognize it or recognizes it as half the size when it does. I'd like to know 1)why this is happening
2) if there's any way to recover the data on the disk.


The HD had been working just fine until a week ago when I suddenly got a message on a reboot, "Specific I/O operation of /Drive/hddisk3/...... was not completely before the the time-out period expired." and Windows would not start.

I figured there was an inssue with one of any I/Os. So, I unplugged all communication cables inclduing the printer, internet, and USB HDDs cables. Then Windows started without any difficulty.

I' m not usre what caused the error message to begin with but teh only thing that was different in this particular reboot was that I have AVG Anti-virus and the program had been saying that the download of that day's updates had not been successful, please download them. But I ignored the message, shut down the machine, and tried to reboot.

Anyway, I got Windows started after unplugging all I/O cables, then I plugged back in the internet and printer cables, and then 2 of the 3 external HDDs I have. All were recognized by my computer within a few seconds and reacquired their original dirve letter assignments. But the very last external HDD did not show up under My Computer.

I went to Disk Management under the Control Panel and found one disk drive that didn't have any drive letter. The unrecognized HDD was supposed to be 500GB, however, in the disk management window, the disk without a dirve letter was 235GB. When I unplugged the 500GB HD, however, the disk without a drive letter disappeared from the list of HDDs in Disk Mangement. So, I figured though the size is half of what it should be, that was the problem HDD.

After playing around with it, I noticed an option to "Activate" the HDD. I think I found it when i right-clicked on the problem HDD under Disk Management. When I clicked on Activate, the drive aquired a letter and become my H drive.

I then went to My computer and saw the H drive showing. hoped that the ordeal was over. but when I tried to open the H drive, my computer says "this hard disk is not formated. Do you want to format." Of course, I didn't format knowing that formatting would delete everything on it.

Why did it suddenly stop working after I unplugged and plugged it back in? Is the issue related to the I/O error message I got on the reboot? Is there anyway to get the data back?

Thanx guys.

 

The external HDD is Fantom G-Force 500GB with USB 2.0 interface by Micronet. How can I check for disk errors? I again checked the device manager, and it doesn't say any brand name. Just say "Removable Disk, No Media". I uninstalled the driver once and scan for new hardware. Then I got the expted "new hardware found" message, but then again just Just say "Removable Disk, No Media". I noticed that the HDD is making clicking noises. I guess it's permanenty damaged and the data is permanently gone?? Thank you for your help! Much appreciated.