Here's 'fdisk -l'. (sdb is a usb disk I connected later.) The warnings seems to corroborate cinap's comment, is it so?

The dump: http://dl.dropbox.com/u/10125317/sda.16.dump
(dd if=/dev/sda of=sda.16.dump bs=4096 count=16)

That should be the 1st. 16 sectors I hope. I checked (dumpe2fs) the bs of sda3 (this partition is intact) to use the above bs. Also, to boot into my Windows, I had fixed the mbr using the Windows 'fixmbr' command. So you will find an intact mbr, and therefore not a very useful thing, the dump will turn out to be.

This exercise is turning out to be interesting. May I ask how you would have worked on the dump, and what could be learnt from looking into it?

And what did you mean by : cat /dev/sd*/ctl, it didn't work for me? I used sda and sda5.

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Warning: Partition 5 does not end on cylinder boundary.
Warning: Partition 6 does not end on cylinder boundary.
Warning: Unable to open /dev/sr0 read-write (Read-only file system).  /dev/sr0 has been opened read-only.
Error: /dev/sr0: unrecognised disk label

Disk /dev/sda: 320 GB, 320070320640 bytes
255 heads, 63 sectors/track, 38913 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        6374    51199123    7  HPFS/NTFS
/dev/sda2            6375       31298   200193997    f  Extended LBA
/dev/sda5            6375       30689   195302205   83  Linux
/dev/sda6           30690       31297     4875727   82  Linux swap
/dev/sda3           31299       37359    48676950   83  Linux
/dev/sda4           37360       37759     3204967   39  Plan 9

Disk /dev/sdb: 1000 GB, 1000202273280 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1          97      779121    b  FAT32
/dev/sdb2              98        1403    10482412   83  Linux
/dev/sdb3            1404      121601   965482402   83  Linux
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