gnu grub version 1.99-21ubuntu3.1 error

[strmy]

Hi!
i have a problem at startup of ubuntu 12.04 64bit.
when i start the computer it says:

GNU GRUB VERSION 1.99-21ubuntu3.1
Minimal BASH- like line editing supported. for the first word, TAB
lists all possible command completions. Anywhere else TAB list possible device or file completions.

if i press tab, it shows a list of some words that don't make sense to me.

when i insert a liveCD there is no response. yes i have selected CD boot in bios, but it starts from hard disc anyway.


Please help.

J.

[darkod]

Were you deleting any partitions? Maybe you deleted the ubuntu partition by accident? Were you changing the boot order in BIOS? Maybe you have good grub2 on one disk and broken grub2 on another one, and you are simply booting from the wrong disk.

It's not possible that it can't boot from the cd. If it can't, then either you are not doing it right, or your cd-rom is faulty, or the cd is faulty. The computer should always be able to start from cd when you tell it to, regardless what is happening with the hard disk.

But if you want, you can try fixing this without the liveCD (although it would be much easier if you can boot the cd in live mode).

At that grub prompt, what does it show if you execute:
ls (small LS)

[strmy]

ls:
(hd0) (hd0,msdos5) (hd0, msdos1)

I've instaled upgrades, have only 1 disk, couldn't delete partition, because ... well i just don't know how to do that

i'll check cd and report.

[darkod]

So, you have only one disk (hd0) which has two partitions, #1 and #5. I guess you have only ubuntu, not a windows dual boot.

In that case, try these commands to boot. Execute them one by one:

insmod part_msdos
insmod ext2
set root=(hd0,msdos1)
linux vmlinuz root=/dev/sda1
initrd initrd.img
boot

See if that boots you.

[strmy]

after linux vmlinuz root=/dev/sda1
i get: invalid file name 'vmlinuz'

[darkod]

OK. Before you start executing the commands, check the exact file names with:
ls (hd0,msdos1)/boot

You should see something like vmlinuz-3.2.0-xx-generic and initrd.img-3.2.0-xx-generic. Note them down.

After that, when you know which files are there exactly, modify the last two lines before boot as:

linux /boot/vmlinuz-3.2.0-xx-generic root=/dev/sda1
initrd /boot/initrd.img-3.2.0-xx-generic

The rest of the commands are the same. In these two just use the filenames you found with the ls command.

See how that goes.

[strmy]

i get list of files, like 20 of them. they're all similar(starting with system.map/abi/config/initrd.img/vmlinuz), but have different numbers - from 20 to 31.

if i use any of these, starting with vmlinuz i get:
error: file not found.

[darkod]

Make sure you use the correct syntax for the filename. If it's there, it should work. Try the ones with the highest -xx- number first, if that doesn't work, the next lower, etc.

Also, try this modification:

linux (hd0,msdos1)/boot/vmlinuz-3.2.0-xx-generic root=/dev/sda1
initrd (hd0,msdos1)/boot/initrd.img-3.2.0-xx-generic

Just make sure you use the correct filenames and it should work.

[darkod]

I'm signing off, just to add this. If those commands managed to boot your ubuntu, open terminal and reinstall grub2 to the MBR with:

sudo grub-install /dev/sda
sudo update-grub

If you can't boot with those commands, then you might have a more serious problem, not just grub2 not booting.

[strmy]

can I try one after the other, or must I type everything for each try, when i try different numbers?

i tried with nr.31 and 1. of these two rows was ok, for second one i got:
couldn't read file