Restoring the MBR on a CD-ROM less Notebook

[Tom H]

On Tue, May 18, 2010 at 3:37 PM, Amichai Rotman <amichai at iglu.org.il> wrote:
> My sister bought a new Asus UL20A. I managed to convince her to give Ubuntu
> a try (it came with Windows 7 pre-installed), So i installed 10.04 on it.
> It has a single 320 Gb HDD, I was very careful not to wipe the recovery
> partition, but I had to cut the original system partition (disk C:) into 2
> partitions for Swap. so:
> It had a Disk C: (I think about 80 Gb in size) and the rest as disk D: for
> data.
> I chose to manually partition the drive during the installation and deleted
> the 80 Gb partition and created a 1024 MB for swap and the rest for /
> (root), the rest - i didn't touch.
> After installation, the last option in the GRUB menu was Windows Vista
> (although it was actually Windows 7). I didn't give it much thought...
> The deal was she tries Ubuntu for a week, then she decides if she wants to
> keep it or go back to Windows 7. Regrettably - she chose the latter.She has
> to go abroad for 3 months and she's affraid she will be stuck and no one
> will know how to help her. She said she had nothing against Linux but...
> I tried to launch the recovery process by pressing F9 during boot - but
> nothing happened. I then tried to boot from that mysterious option on the
> menu - an what da ya know ! it's the recovery process! So it went about
> recovering - just as if I pressed F9 - and then told me the recovery was
> done and I should click OK to shut down.
> And here is the part I need help with: The next time I pressed the power
> button - it says there is an error and gives me the "grub rescue>" prompt...
> Please help me! There is no CD ROM drive, no recovery DVD media supplied (a
> note that came with the computer says one is not supplied with this model).
> How do I boot from USB stick and recover the Windows 7 MBR / Boot loader?!
> All I have is my on Ubuntu Lucid on both my Desktop and my Netbook...

At the grub rescue prompt:

Run "ls" to display your disks and partitions

Run "set" and check the values of "root" and "prefix"

If "root" and "prefix" are incorrect (if you do not know what they
should be, run "ls (hdX,Y)/boot" for the different values of X and Y
since search isn't available in rescue mode), run
set root=(hdX,Y)
set prefix=(hdX,Y)/boot/grub
to set them to the correct values

Run
insmod normal.mod
or, if necessary,
insmod /boot/grub/normal.mod

Run
linux /boot/vmlinuz-2.6.x.x root=/dev/sdXY ro
initrd /boot/initrd.img-2.6.x.x
boot
(use tab completion)