My father had an external HD unit that he'd been backing up the movies he edits onto. His machine won't take a second HD, so there wasn't any alternative.
He told me that his HD was having an odd error, that it makes a little musical tune about a dozen times when it's powered on, and never manages to mount.
I'd tried putting it in my new PC just now, and it gives the same music tune, so it's not the external exncosure, but the HD itself.
It's a Maxtor Diamondmax Plus 9, 200 GB. Their website has no info for support on it. I figure it's dead in the water, but I don't know if anyone here has encountered and/or fixed an issue like this. If we can just get the data off, that'd be helpful as well.