Ho dato i comandi da teminale che mi hai suggerito. Ho riavviato, ma il problema permane.
Incollo qui i risultati dei tuoi comandi.
Ho due partizioni Ubuntu, una per la versione 10.10, che dovrebbe essere /dev/sda7 e un'altra, per la versione 12.04.01, su cui sto lavorando e che dà problemi in modalità ripristino. Dovrebbe essere /dev/sda8.
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
proc /proc proc nodev,noexec,nosuid 0 0
# / was on /dev/sda8 during installation
UUID=11723a2c-03ad-4f66-8ed4-c214c720cf26 / ext4 errors=remount-ro 0 1
# swap was on /dev/sda5 during installation
UUID=6dcf63a6-d7ba-4962-811b-51a4efe152bc none swap sw 0 0
/dev/sda6 /media/Dati ntfs-3g silent,umask=000,locale=it_IT.utf8 0 0
***
/dev/sda8 on / type ext4 (rw,errors=remount-ro)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
none on /sys/fs/fuse/connections type fusectl (rw)
none on /sys/kernel/debug type debugfs (rw)
none on /sys/kernel/security type securityfs (rw)
udev on /dev type devtmpfs (rw,mode=0755)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620)
tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755)
none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880)
none on /run/shm type tmpfs (rw,nosuid,nodev)
/dev/sda6 on /media/Dati type fuseblk (rw,nosuid,nodev,allow_other,default_permissions,blksize=4096)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev)
gvfs-fuse-daemon on /home/guido/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=guido)
***
Disk /dev/sda: 320.1 GB, 320072933376 bytes
255 testine, 63 settori/tracce, 38913 cilindri, totale 625142448 settori
Unità = settori di 1 * 512 = 512 byte
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Identificativo disco: 0xf3a8c919
Dispositivo Boot Start End Blocks Id System
/dev/sda1 2048 29362175 14680064 27 Hidden NTFS WinRE
/dev/sda2 * 29362176 29566975 102400 7 HPFS/NTFS/exFAT
/dev/sda3 29566976 133031935 51732480 7 HPFS/NTFS/exFAT
/dev/sda4 133033982 625141759 246053889 5 Esteso
Partition 4 does not start on physical sector boundary.
/dev/sda5 247203840 278194175 15495168 82 Linux swap / Solaris
/dev/sda6 278196224 625141759 173472768 7 HPFS/NTFS/exFAT
/dev/sda7 194426880 247201791 26387456 83 Linux
/dev/sda8 133036032 194424831 30694400 83 Linux
Le voci nella tabella delle partizioni non sono nello stesso ordine del disco
