I've not been able to get to my ubuntu for a fair while.
I use Super Grub Disk to boot it rather than have grub on the MBR.
But here I am posting this with Ubuntu and its not a Live CD session.
I had considered doing a reinstall when I first hit the "corrupt superblock" problem but as we were in the middle of buying a house I gave it a miss.
When I was in the house I had plenty of excuses to sort out the computer rather than pull off wallpaper and so on ( the house is a building site).
I stuck in
Knoppix and opted to go to non graphic mode - I was looking for a few files on the ubuntu system. knoppix told me to run ext2fsck before mounting - i did and it fixed it.
Marvellous.