I have a a Maxtor Diamond Plus 9 160GB SATA/150HDD.

It used to live in a CCTV controller until a burglar had a go at it, I found the box under a hedge a few months later amazingly it still works apart from the disk drive.

The disk spins and the head mechanism moves during boot up, the heads move in and out but produce a chirruping sound.

I bought another one off ebay the other day to swop over the logic boards, sadly it made no difference so it would suggest that the problem is with the disk heads or disk surface.

If the disk heads are u/s then the data on the disk drive is still valid and the last file will be of the burglar's ugly face.

On the other hand it may indicate that heads cannot find any data tracks to read.

There is no scratching sound so that would suggest the disk surface is still good.

I look forward to hearing if anyone knows what this noise indicates.
Thanks

That heads are broken.

Perhaps give the drive to the police and tell them the drive is broken but it might have something on it about the bulgerly. They will take it, recover the data for free and catch the guy, if anything useful on it.