Bem não dá na mesma, deixo aqui os dados
vagarinho@vagarinho-desktop:~$ sudo fdisk -l
Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xaf63af63
Device Boot Start End Blocks Id System
/dev/sda1 * 1 18662 149902483+ 83 Linux
/dev/sda2 18663 19457 6385837+ 5 Extended
/dev/sda5 18663 19457 6385806 82 Linux swap / Solaris
Disk /dev/sdb: 320.1 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x05000000
Disk /dev/sdb doesn't contain a valid partition table
Disk /dev/sdc: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x03a75d49
Device Boot Start End Blocks Id System
/dev/sdc1 * 1 60802 488384512 7 HPFS/NTFS
Disk /dev/sdd: 320.1 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x9ed30e3d
Device Boot Start End Blocks Id System
/dev/sdd1 * 1 77827 625139712 7 HPFS/NTFS
No comando "sudo mount /dev/sda2 /mnt" troquei o 2 pelo 1
depois no comando "sudo grub-install --root-directory=/mnt /dev/sda "
dá este erro vagarinho@vagarinho-desktop:~$ sudo grub-install --root-directory=/mnt /dev/sda Probing devices to guess BIOS drives. This may take a long time.