Hitachi Deskstar 500GB not recognized

[Jingleboy]

Hello there, I was wondering if I could get some advice (and potentially solutions) to problem that has occurred to my External Hard Drive?

The story: I bought my External Hard Drive about 2 years ago, and has worked fine up until now. It connects to my PC via USB using an ATA to USB board, as most External HDD do. About a month ago though, the External HDD stopped booting properly when turned on, as it just slowly span its disc until it gave up and stopped. After tinkering with it and eventually giving up, I went on Vacation for a while then came back to it, deciding to swap power supplies to see if that'd work.

Lo and behold, it boots up and lives again, so I discard the faulty power supply (Which is a 6-pin DIN connect) however, the current temporary power supply isn't the best either, and the access light on the front of the External HDD case keeps flickering from green to red. In my haste, I decided to try and copy as much of the data I could salvage while I still had access. This is where the problem starts.

During the copying process, the External HDD light eventually became solid red and the transfer dies. Since nothing was happening, I decided to turn off the External HDD. I eventually went and bought a brand new power supply that works fine, and went and rigged it up to the External HDD. Turned it on and Windows (I run Windows 7) goes "Boo-bee" to confirm it's recognized something has connected and then... nothing. No auto run dialogue, the External HDD is not under "My Computer" yet it still installs the driver to my PC, and it says "Mass USB storage device detected".

Anyone got any understanding or advice on how to undo this? Thanks in advance.

My External HDD is a Hitachi Deskstar, but I canl provide more details on request.

[Alexii]

i am suspecting bad / slow sectors. There is a posibility that the read / write heads are not working properly. Need diagnostics on this drive to be safe. For example i can suggest bit by bit copy of ur bad drive on a good drive. But if the heads are week - this will finish them off for good. Contact PCimage from this forum if u want , he can offer a free diagnostics for u i am sure.
But if u want to go DIY only - then take ur HDD out of the external enclosure , connect it to the motherboard directly with an empty HDD and run a bit by bit copy from bad one on to good one. Keep fingers crossed.

[Jingleboy]

If I plug in this Hard Drive to another machine it still isn't recognized in a manor that will let me access it. That includes plugging it in via S-ATA. The drive comes up with no name in the BIOS menu, but is still detected by the system as it doesn't say [Nothing connected]

[Clusterox]

Try mhdd and if you get BSY for a couple of second than READY afterward, but still no access, that is the head problem.

It's a known thing with Hitachis.