NTFS Partition gets auto-corrupt, becomes RAW and unreadable

I have dual boot on my machine: Windows 8 and Ubuntu 11.10.
Suddenly, one of my partitions went corrupt.

On Windows, it's showing this error.

Location is not available.
E:/ is not available.
The file or directory is corrupted and unreadable.

Here is the snapshot of Disk Management on my Windows 8 developer beta.

Here, I have:  
The first partition: ext4 filesystem: ubuntu 11.10  
The second partition: swap  
The third partition: Has my precious data(***NOT WORKIING, type auto-changed from NTFS to RAW***)  
The fourth partition: Has data too, and working  
The fifth partition: The Windows partition(Windows is installed on this one)  

On Ubuntu,
When I try to mount the partition via nautilus, I get

Error mounting: mount: wrong fs type, bad option, bad superblock on /dev/sda2,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

On running this command,

jatin@silverSpoon:~$ dmesg | tail
[   24.754970] ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[   35.552058] wlan0: no IPv6 routers present
[  217.511030] exe (2592): /proc/2592/oom_adj is deprecated, please use /proc/2592/oom_score_adj instead.
[ 1420.818037] NTFS driver 2.1.30 [Flags: R/O MODULE].
[ 1420.853141] __ntfs_error: 27 callbacks suppressed
[ 1420.853150] NTFS-fs error (device sda2): ntfs_mapping_pairs_decompress(): Corrupt attribute.  deltaxcn = 0xe37f, max_cluster = 0xe34b
[ 1420.853157] NTFS-fs error (device sda2): ntfs_mapping_pairs_decompress(): Corrupt mapping pairs array in non-resident attribute.
[ 1420.853163] NTFS-fs error (device sda2): ntfs_read_inode_mount(): ntfs_mapping_pairs_decompress() failed with error code -5.  $MFT is corrupt.
[ 1420.853169] NTFS-fs error (device sda2): ntfs_read_inode_mount(): Failed. Marking inode as bad.
[ 1420.853175] NTFS-fs error (device sda2): ntfs_fill_super(): Failed to load essential metadata.

Running fdisk shows this:

jatin@silverSpoon:~$ fdisk /dev/sda -l 
Cannot open /dev/sda

Running fsck, shows this:

jatin@silverSpoon:~$ sudo fsck /dev/sda
fsck from util-linux 2.19.1
e2fsck 1.41.14 (22-Dec-2010)
fsck.ext2: Device or resource busy while trying to open /dev/sda
Filesystem mounted or opened exclusively by another program?

Mt /etc/fstab file shows:

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    nodev,noexec,nosuid 0       0
# / was on /dev/sda3 during installation
UUID=07d58b27-8c22-466f-a770-dc720d6be71c /               ext4    errors=remount-ro 0       1
# swap was on /dev/sda5 during installation
#UUID=bd6782f4-cf13-4a81-bc68-d72ab26b1113 none            swap    sw              0       0
/dev/mapper/cryptswap1 none swap sw 0 0

and fdisk shows this:

jatin@silverSpoon:~$ sudo fdisk -l

Disk /dev/sda: 320.1 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xaa692010

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048   123383807    61690880    7  HPFS/NTFS/exFAT
/dev/sda2       123383808   429830143   153223168    7  HPFS/NTFS/exFAT
/dev/sda3       429830144   461078527    15624192   83  Linux
/dev/sda4       461080574   625141759    82030593    5  Extended
/dev/sda5       461080576   466937855     2928640   82  Linux swap / Solaris
/dev/sda6       466939904   625141759    79100928    7  HPFS/NTFS/exFAT

Disk /dev/mapper/cryptswap1: 2998 MB, 2998927360 bytes
255 heads, 63 sectors/track, 364 cylinders, total 5857280 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xaed90ab6

Disk /dev/mapper/cryptswap1 doesn't contain a valid partition table

And at last, file -s /dev/sda2 shows

jatin@silverSpoon:~$ sudo file -s /dev/sda2
/dev/sda2: x86 boot sector, code offset 0x52, OEM-ID "NTFS    ", sectors/cluster 8, reserved sectors 0, Media descriptor 0xf8, heads 255, hidden sectors 123383808, dos < 4.0 BootSector (0x80)