please dont get offended by "MUST WORK".

When you say about SMART "nothing stood out", what message was coming out?

I can't advice on how to cure it, but there is set of query-type commands you can issue safely and post log, maybe someone else respond.

When command is rejected because of CERT, press ^R to load CERT and repeat command (not sure on F3).

The disk is a Barracuda 7200.12 750GB ST3750528AS
Firmware HP34.

The drive is not recognized by BIOS. I have tried several systems with the same result. Further, whatever the drive is doing, seems to kill the whole SATA bus as no other SATA device is recognized by BIOS in a system when this drive is attached.

I have attempted to diagnose the drive using SeaTools for DOS, but the software does not see the drive. I have downloaded a copy of MHDD and will try that shortly, but am not expecting results given the inability to even recognize the drive so far.

I have access to the Diagnostic command line, but I am not certain what do do there. I have read the list commands at http://www.itosaka.com/WordPress/wp-con ... ommand.pdf but (a) some of the commands do not work (ex. in level T, I attempted the command D to display logs, but get a response "Invalid Diag Cmd") and (b) Im still not sure what I should be doing.

In anycase, the drive spins up and spins down without problem, and displaying the SMART Critical Log entries (N8) returns nothing.

As far as sounds go, the drive is mostly quiet. I hear two slight ticks when the drive spins up, but I have certainly heard much more noise from drives that were functioning.

Any suggestions on how to diagnose what is wrong with the drive would be greatly appreciated. Once I know the problem, I can make a decision to attempt a DIY or contract with a professional.

N5 and N6 listed the SMART values and thresholds. I compared one to the other and none of the values was over the threshold.

N8 was supposed to return the critical logs, but apparently there was no critical log entries as it returned nothing at all.

F3 T>
Current R/W User LBA 00000000 LLL CHS 000000.0.0000 PLP CHS 000000.0.0000
R/W Status 1 R/W Error 00000080 Ready

[...]
F3 T>V4

Reassigned Sectors List
Entries: 0000, Retrieved: 0000, Alts: 0000, Removed: 061B, Pending: 0000, GList: 0000, RList: 0000

I see error message from the dot command, but it is unclear what it means. It seems G-list has been cleared, Removed 0x81B entries. Does it means system remembers removed G-list entries?No critical logs, no warnings, but all data lockup. Classic firmware corruption. Information how to fix it is still kept secret. I wonder if Seagate had been threatened with class action for such practice?

Unless you follow another advice, you can try 1>N1 command, which seems is not harmful (as opposed to T>m2xxx variants), but helps in some cases.

I re-ran the diagnostic commands that SAjunky has recommended earlier, intending to post and ask for further advice. One thing I noticed was the V4 information had all been cleared.

My only concern is that your P-list, called User Slip Defect List is empty, so I am concern your clone is good. SMART operation shouldn't clean P-list, it could be in result of previous translator regeneration (if attempted). But loki don't complain, perhaps not important.

That might be a concern if I planned to reuse the drive, but I may be crazy, but I aint stupid.

Agreed, nobody would try to reuse such drive. It is nice it could just complete cloning. But my concern was not about reusing, but validity of cloned data. P-list hold entries created during factory certification tests. Your data had been written using existing remapping structure. If you loose this structure, it would point your readings to the original sector which never contained your data, as was excluded from accessing 'forever'. Replacement sector keeps your data and you just lost pointer to it. That was my concern. Please correct me if I am wrong.