is there any unusual noise, clicking, beeping
it stops spinning ?
what model is it ?

you can buy a cheap TTL adaptor :

http://www.hddoracle.com/viewtopic.php?f=46&t=192

Conect it like this :

http://www.hddoracle.com/viewtopic.php?f=6&t=193

And look for the drive output.

DO NOT ISSUE THE 7200.11 FIX COMMANDS OR ANY COMMAND AT ALL

Of course this will not help.

The drive is not even detected by BIOS even when pluged directly to the motherboard....

Well ... I'm verry sorry but i don't think you can have both....

Most likely the drive have some sort of translator problem that might involve damaged defect lists or even media damage/ failing heads.

With luck the damage it's only localized to the translator sub-system, and if so it might be a very cheap fix when done correctly. And this is the tricky part.

DO NOT APPLY THE 7200.11 FIX on this drive, as if there are defects on the non-resident G-List that list will be gone and it will be harder (and more expensive) to get your data back.

I would say as the data is important to you to just bit the bullet and pay for professional data recovery. Please chose a reputable data recovery firm and not an ordinary computer repair shop that most likely will blindly apply the 7200.11 fix to your drive.

If you decide that the data is not important at all and you want to attempt a do-it-yourself try with a chance to cause further damage to the drive (very likely) you can do as suggested, order a TTL adaptor and start by checking if you have defects on the Non-Resident G-list by issuing the CTRL+Z and at level F3 T> the command V40.

If the non-resident G-List is empty and only then i would as well check the G-List - V80 and then i would attempt a translator regen taking intro account the AltList - m0,6,3,,,,,22 and see if you can gain access to all LBA of the drive.

If so i would then disable rellocation :

http://www.hddoracle.com/viewtopic.php?f=83&t=557

And attempt to recover the data by cloning the drive and running logic recovery software on the clone if needed :

http://www.hddoracle.com/viewtopic.php?f=117&t=1410

http://www.hddoracle.com/viewtopic.php? ... 1409#p7237

To better understand why you should NEVER attempt to regen the translator without taking intro account the defects on the non-resident G-List read my article here :

http://www.hddoracle.com/viewtopic.php?f=46&t=1402

Idea is that because of shift points in the translator sub-system you will end up with partial access only from the fist sectors on non.resident g-list that is ignored up untill the end of the drive. It will be like adding/removing a P-List defect as the non-resident g-list is a last step at factory to add extra "primary" defects to defect list that acts as a p-list and NOT as a g-list.

Regards and good luck.

Regards.