Hard disk detected at first but not after OS is selected for boot

[TimeManx]

Well, my Seagate Barracuda 500GB suffered a power failure. It is detected at POST and even GRUB loads off it. But after I select an OS, it's partition isn't detected. When I select linux, the kernel is successfully loaded from it's partition (so that partition is found) but it gives me a kernel panic saying that the root partition wasn't found. As for Windows 7, GRUB just shows a message saying the partition couldn't be found.
On booting into Win7 on another hard disk, the partitions of the hard disk in question aren't present.
And after that when I restart, the hard disk isn't even detected at POST. It is again detected only when I unplug the power from the motherboard, plug it back in and then switch on.
So, I am hoping that the data can be somehow salvaged. I don't care about the hard disk. I just care about the data.

 

[ryanrich83]

If loading to an OS on another drive won't let you access the partitions in question... Not good.

Try to find a local data recovery provider and see if anything can be salvaged off the drive.

 

[apache_lives]

test your hardware

where is your data backup?

 

[TimeManx]

test your hardware

The hardwares fine. Plugging in other hard disks in it's place works fine.

where is your data backup?

I have a little backup but not all of it. It was a lot to have a backup of. Actually, I never really thought this would happen.

 

[popatim]

From what it sounds like to me all your data is still there, you just need to repair the partition table. How you do that with grun is a mystery to me. Do you have a backup of the partition table?

I'm not familiar enough with grub but normally I would just use fdisk.

Have you tried 'Boot Repair' ?

 

[TimeManx]

From what it sounds like to me all your data is still there, you just need to repair the partition table. How you do that with grun is a mystery to me. Do you have a backup of the partition table?

I'm not familiar enough with grub but normally I would just use fdisk.

Have you tried 'Boot Repair' ?

I tried creating a new partition table using TestDisk but it fails with a write error. Actually everything I tried fails with a write error.
Even SeaTools fails to perform a long test.

These are the errors in Boot Repair's log

[ 45.342661] sd 0:0:1:0: [sda] CDB: Read(10): 28 00 0e f6 40 80 00 00 08 00
[ 45.342669] end_request: I/O error, dev sda, sector 251019392
[ 45.342736] sd 0:0:1:0: [sda] Unhandled error code
[ 45.342738] sd 0:0:1:0: [sda] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK