After grub rescue problem ubuntu live will not install

[xrobbo]

Hello everybody,
I had a problem with the grub. When I turn my 12.04 ubuntu laptop ubunt won't start and the grub rescue message appear.
I've tried to solve with no success, so I decided to reinstall ubuntu from a bootable live usb key. I succeed in booting from the key but then cannot start the installation of OS on the machine. If I launch gparted, it cannot find the partitioning of the hard disk and continue sarching for it.
I'm quite desperate. Any suggestion about how to proceed would be very very welcomed.
thanks in advance

[darkod]

Boot the usb in live mode, open terminal and post the output of:

sudo parted -l (small L)
sudo fdisk -l

[xrobbo]

Hi, and thanks. The first command does not produce any output. The computer keep on processing, I have waited 10 minutes.
Here is the output of fdisk -l

Disk /dev/sda: 320.1 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xafad6a08

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 206847 102400 7 HPFS/NTFS/exFAT
/dev/sda2 206848 41453567 20623360 7 HPFS/NTFS/exFAT
/dev/sda3 41453568 82311167 20428800 83 Linux
/dev/sda4 82313214 625141759 271414273 5 Extended
/dev/sda5 82313216 621887487 269787136 83 Linux
/dev/sda6 621889536 625141759 1626112 82 Linux swap / Solaris

Disk /dev/sdb: 4022 MB, 4022337536 bytes
255 heads, 63 sectors/track, 489 cylinders, total 7856128 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0217934c

Device Boot Start End Blocks Id System
/dev/sdb1 * 63 7856127 3928032+ e W95 FAT16 (LBA)
ubuntu@ubuntu:~$

[darkod]

Do you know which one is your / partition, sda3 or sda5? There are two Linux partitions on the disk, one of them might be a /home partition if you installed it like that earlier.

[xrobbo]

the operating system is on sda3, whereas sda5 contains the home.

[darkod]

OK, from live mode try reinstalling grub2 on the MBR of sda with:

sudo mount /dev/sda3 /mnt
sudo grub-install --root-directory=/mnt /dev/sda

That will reinstall it on the MBR but it still might not work if the problem is different. Restart and see if it helped.

[xrobbo]

This I already tried. The problem is that when I launch the first command the laptop starts processing and never stops. I have waited for more than 30 minutes before giving up. Is that possible?
Also, the same happened when I launched gparted, and also when I tried to install ubuntu from the usb key.
It seems to me that any time I launch a command that operates on the hard disk I get troubles.
Anyway, the most important question is: supposing I launch the command you suggest, shall I wait for how long before considering that nothing is going to happen?

[xrobbo]

Just a further note: I have a brand new dell 3350 with intel i5 on it, so slowness does not depend upon the hardware.

[darkod]

No, the results should be immediate.

Unfortunately, commands not finishing their task fast as soon as they start accessing the HDD sounds like faulty hdd to me.

I had a similar case with two faulty desktop disks I was given to see if they can work or not. They look normal on first view, fdisk will even see them and print the partitions list, but as soon as you give a command accessing the disk, the command never finishes and the disk can't be seen any more.

I might be wrong but this looks to me like hardware failure, or close to it.

[xrobbo]

This is what I feared too. Any way to check if this is really so?

[darkod]

Not sure. You might run a SMART test with smartmontools. You need to install them first. I think you should be able to do that from live mode.

Except that, the only other test I can think of is trying to use the disk. If it continues blocking as soon as any command tries to access it, I guess it's clear.