Is there a disk reader where you can physically take the hard drive discs out of your defective drive and put them into a type of drive to read the data? something like a dvd reader but with steel hd disc readability?
Only way you are likely to have success salvaging anything is by booting to a different drive with the failed drive hooked up as a "slave". If the drive comes up as not recognized then you are out of luck (unless you want to drop a bunch of money having a third party company try as Traildriver suggested).
I would like to know what OS your using.
Why I am saying this is to help you it may be case of a few bad sectors on the HD, most HDD`s have spare sectors reserved in case a few become unreadable or writable to.
It may be the case, it may not. I will get to this and explain how to do it and it may work for you. Also if you could have a listen to the drive when you power the PC on.
Loud clicking is a sign of a bad sector, a read head gone bad. or a sticky read head.
So you need to check for that, sometimes a light tap on the side, not the top of the drive can be enough to set it right.
If the drive is showing in windows then I would advise you right click on the drive. Then go to properties.
Click on the tools tab,Click on the error checking tab, check now.
Restart windows, and it should go into an dos based error checking mode, its will take some time with a 2 Tb drive size, so be patient. if it can recover the sectors that are bad it will use the spare good ones and tell the drive to ignore the bad ones. You may get lucky or may not but you never went in depth as to the drives Symptoms.
Anyway I hope it helps you, all the best Shaun.