Help fixing system that won't boot

[Crispin Wellington]

The first thing I would do is use the CD rescue system to make a backup of
the filesystem onto another computer or disk. As an older machine the disk
may be starting to fail and so while you can access your files, a backup
may be in order.

It may no longer be booting if the boot partition or efi filesystem is
damaged. You can try re-running grub on the disk from the rescue image to
reinstall the boot partition. You would do this by

1. booting the rescue CD. (Backup the harddrive filesystem.)
2. reconstructing the mount hierarchy on a mount within the new system. If
your old system has everything in one root partition, this is as simple as
mounting that partition under, say, /mnt. It may be automounted already by
the rescue CD.
3. 'chroot' into your old system. If it's mounted on /mnt, it would be:
"chroot /mnt /bin/bash --login" . This starts /bin/bash, your shell, from
your on disk (/mnt) filesystem, so drops you into a shell on your old
system.
4. update your grub config with: "update-grub". No errors should occur.
5. reinstall your grub boot partition with: "grub-install /dev/sda".
Replace /dev/sda with the device ndoe for you'r booting harddrive if it's
not /dev/sda. No errors should occur.

This might make your system bootable again.

Crispin


On Fri, Apr 11, 2014 at 10:22 AM, Linda <haniganwork at earthlink.net> wrote:

> I have 12.04 LTS installed on an older machine. It totally froze today and
> I had to try turning it off and back on. Unfortunately it fails to boot.
> After alot of searching I found a copy of 12.04 LTS that will fit on a 700
> MB CD so I can know boot from the CD and view my filesystem.  How do I go
> about fixing it so it can boot. When I tried looking all I found was what
> to do if you goofed up a dual boot machine but this one only has ubuntu
> 12.04 on it. In help sending me in the right direction to fix this would be
> greatly appreciated.
>                    Thanks
>                    Linda
>
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