Unable to boot into Lucid Lynx 10.04 beta 1

Reinstall the Lucid....that will take less time, Secondly Lucid is still under development stage so be prepared for such hiccups....

IMO i think the problem is not with Lucid, because I had booted 3-4 times to Lucid which felt more stable than Karmic :) . But, some time later, computer got shut down abruptly due to power cut and now, it cant boot.

I upgraded from Karmic using "update-manager -d" and dont have its CD. Moreover, karmic had a lot of packages and settings that I cant afford to loose.

Boot to liveCD and fsck your internal partitions to make sure the data has not been garbaged

I am on livecd right now. Below is the result of "sudo fdisk -l"

   Device Boot Start End Blocks Id System
/dev/sda1 1 3917 31463271 7 HPFS/NTFS
/dev/sda2 3918 10444 52428127+ 7 HPFS/NTFS
/dev/sda3 10445 15671 41985877+ 7 HPFS/NTFS
/dev/sda4 15672 19457 30411045 5 Extended
/dev/sda5 * 15672 17711 16386268+ 83 Linux
/dev/sda6 17712 19457 14024713+ 83 Linux
--------------------------------------------------------------------------------
$sudo fsck -TV /dev/sda

[/sbin/fsck.ext2 (1) -- /dev/sda] fsck.ext2 /dev/sda
e2fsck 1.41.9 (22-Aug-2009)
fsck.ext2: Superblock invalid, trying backup blocks...
fsck.ext2: Bad magic number in super-block while trying to open /dev/sda

The superblock could not be read or does not describe a correct ext2
filesystem. If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
    e2fsck -b 8193 <device>
---------------------------------------------------------------------------------
$sudo fsck -TV /dev/sda[i] //where i is 1,2,3

fsck: fsck.ntfs: not found
fsck: Error 2 while executing fsck.ntfs for /dev/sda3
-----------------------------------------------------------------------------------
$sudo fsck -TV /dev/sda4

[/sbin/fsck.ext2 (1) -- /dev/sda4] fsck.ext2 /dev/sda4
e2fsck 1.41.9 (22-Aug-2009)
fsck.ext2: Attempt to read block from filesystem resulted in short read while trying to open /dev/sda4
Could this be a zero-length partition?
----------------------------------------------------------------------------------
$sudo fsck -TV /dev/sda5

[/sbin/fsck.ext4 (1) -- /dev/sda5] fsck.ext4 /dev/sda5
e2fsck 1.41.9 (22-Aug-2009)
/dev/sda5: clean, 167620/1026000 files, 2009843/4096000 blocks
------------------------------------------------------------------------------------
$sudo fsck -TV /dev/sda6

[/sbin/fsck.ext4 (1) -- /dev/sda6] fsck.ext4 /dev/sda6
e2fsck 1.41.9 (22-Aug-2009)
/dev/sda6: clean, 72488/876544 files, 912227/3506176 blocks
-------------------------------------------------------------------------------------

Something is wrong with /dev/sda right?
How do i recover now?

Something is wrong with /dev/sda right?
How do i recover now?

$$ sudo e2fsck -b 8193 /dev/sda

e2fsck 1.41.9 (22-Aug-2009)
e2fsck: Bad magic number in super-block while trying to open /dev/sda

The superblock could not be read or does not describe a correct ext2
filesystem. If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
    e2fsck -b 8193 <device>

Souds like thefile system is damagedmost likely due to the random power off.

I'd go for a reinstall / restore data from backup.