my hdd failing (or maybe totally dead) i've connected the hdd via USB but it doesn't appear in fdisk

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0xe9fb38fb

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048      206847      102400    7  HPFS/NTFS/exFAT
/dev/sda2          206848    40959999    20376576    7  HPFS/NTFS/exFAT
/dev/sda4        40962046   976771071   467904513    5  Extended
Partition 4 does not start on physical sector boundary.
/dev/sda5        82913280    86910975     1998848   82  Linux swap / Solaris
/dev/sda6        86913024   394113023   153600000    7  HPFS/NTFS/exFAT
/dev/sda7        40962048    82913279    20975616   83  Linux
/dev/sda8       394122708   976768064   291322678+   7  HPFS/NTFS/exFAT
Partition 8 does not start on physical sector boundary.

no sdc appears here , BUT it's appears on /dev/

rootghost-lap:/home/ghost# ls /dev/sd*
/dev/sda   /dev/sda2  /dev/sda5  /dev/sda8  /dev/sdb  /dev/sdc1   /dev/sdc2  /dev/sdc6  /dev/sdc8
/dev/sda1  /dev/sda4  /dev/sda6  /dev/sda9  /dev/sdc  /dev/sdc10  /dev/sdc5  /dev/sdc7  /dev/sdc9

also it appears in proc Code:

rootghost-lap:/home/ghost# cat /proc/partitions 
major minor  #blocks  name

   8        0  488386584 sda
   8        1     102400 sda1
   8        2   20376576 sda2
   8        4          1 sda4
   8        5    1998848 sda5
   8        6  153600000 sda6
   8        8  291322678 sda8
   8        9   20975616 sda9
  11        0    1048575 sr0
  11        1      99136 sr1
   8       32  244198583 sdc
   8       33   14651248 sdc1
   8       34          1 sdc2
   8       37   15380480 sdc5
   8       38    4153344 sdc6
   8       39   48829536 sdc7
   8       40   48829536 sdc8
   8       41  110374551 sdc9
   8       42    1975963 sdc10

and dmesg :

[10604.777168] end_request: I/O error, dev sdc, sector 1 
[10604.817238] sd 26:0:0:0: [sdc]  Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE 
[10604.817243] sd 26:0:0:0: [sdc]  Sense Key : Aborted Command [current]  
[10604.817248] sd 26:0:0:0: [sdc]  Add. Sense: No additional sense information 
[10604.817253] sd 26:0:0:0: [sdc] CDB: Read(10): 28 00 00 00 00 02 00 00 06 00

ok now , let's see what i've tried testdisk to check for partitions -- failed dd to copy data from /dev/sdcX -- provide strange output size for example /dev/sdc1 is about 15G , the output for dd is 62G+ so i had to cancle it safecopy successfully made an image for partitons , but can't fix images, can't mount it, can't do any thing with it

and some other tools i've tried and all failed , so any idea ?