[F9] laptop not booting - reinstall MBR?

Phil Meyer pmeyer at themeyerfarm.com
Wed Jul 9 16:56:46 UTC 2008

Don Levey wrote:
> My F9 laptop won't boot this morning - I go through the POST, but when 
> I ordinarily get to the "Hit Enter for options" boot screen, all I get 
> is:
>     GRUB
> at the top left of my screen.  Does this mean I need to reinstall grub 
> and the MBR?  I can access the HD via a liveCD, and everything *seems* 
> OK from what I can tell.  Any thoughts?
> Thanks,
>  -Don

This condition occurs whenever the BIOS changes the drive order.

First things to check:

Do you have a USB drive plugged in?  A camera, ipod, memory card, or 
thumb drive may all have this affect on some BIOS.  Unplug them before 
powering on the system and you might boot normally.

Did you add an internal hard drive since the last time you booted?
Did you make any modifications to the BIOS since the last time you booted?
Did the BIOS battery expire and force you to hit F1 to continue the boot 

All of these factors, and more, can cause the BIOS to report a different 
drive order to grub.
Only in the case of a new drive should you be forced to fix the MBR, and 
then only if the BIOS insists on calling the new drive a lower order 
than the existing one.

To repair the MBR:

boot a rescue CD
# chroot /mnt/sysimage
# grub-install /dev/sda

On some systems, it has been necessary to use old arguments:

# grub-install --no-floppy --recheck /dev/sda

# exit

That should do it.

Good luck!

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