My Seagate Barracuda 7200.11 appears to have stopped functioning all of a sudden. A couple of days ago while I was using it the computer stop recognizing it without any warring. When I restarted the machine it recognized it and started to work. This happened a couple of times then this weekend I left the computer unattended for a day or two and when I came back the disk was making unusual grinding sound and the disk stop working and computer stop detecting it. Tried restarting but didn't work.

The disk size is 1.5 TB, it has 10 years of my data. How can I diagnose the issue further and recover data from the disk

When It started to fail, you should have made backups.
Now, maybe the best thing it to take it to a PRO for diagnosis.

If it's not detected and make noises, probably some head problem...

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Now it doesn't make noise but It can't be detected.

What firmware version? It could be infamous firmware bug. If it is a case, it can be repaired and bring your data back. Search for "7200.11 BSY" or 0 LBA bug.

The noises were before the failure?

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Yes

Firmware: CC1H

Plenty search hits:
how-deal-the-5tb-with-firmwire-cc1h-7200-t15466.html
http://www.msfn.org/board/topic/128807- ... __st__3600
http://www.bluescreenofdeath.org/?tag=cc1h
You need identify what kind of failure it is, "0 LBA" "BSY" or not related. Different action required.

pclab is here, will assist, I am not experienced at all, just overheard...