Ubuntu – Ubuntu 12.04 upgrade: Grub update-grub fails after update

From your BootInfo Script, I can see that GRUB2 resides erroneously on /sda1, your Windows boot partition. I'm not much into Windows anymore, but from what I know there are tools on the Windows CD that allow restoration of bootsectors. You need to boot from the Windows CD and start the repair mode. On the command line, you can try

bootrec.exe /fixboot

to restore your Windows partition boot sector.

Then, however, you won't be able to boot Ubuntu, because there will be no more GRUB2. GRUB2 should have been installed in the MBR of /sda which is not so in your case. This means you will either have to reinstall GRUB (using a Ubuntu live CD) there, or you may find it less time consuming to reinstall Ubuntu as a whole. The latter should not be a great thing if you only installed it recently for testing. In any case, take note that you should not install Grub2 on your Windows boot sector again.

Your Grub file seems ok. I suggest installing Grub2 manually again. First, start Ubuntu from USB stick and do not mount your installed Ubuntu. Open a terminal and apply those commands:

sudo mount /dev/sda1 /mnt
sudo mount --bind /dev /mnt/dev
sudo mount --bind /dev/pts  /mnt/dev/pts
sudo mount --bind /proc /mnt/proc
sudo mount --bind /sys  /mnt/sys
sudo chroot /mnt
grub-install --force /dev/sda

You can check if it is OK or not with:

grub-install --recheck --force /dev/sda

If everything is ok, unmount all the things and quit:

exit
sudo umount /mnt/dev/pts
sudo umount /mnt/dev
sudo umount /mnt/proc
sudo umount /mnt/sys
sudo umount /mnt
sudo reboot