«Перезагрузите компьютер и выберите подходящее загрузочное устройство» во второй раз

Я использую Ubuntu 12.04 и Windows 7 уже довольно давно. Несколько недель назад я получил сообщение об ошибке ниже, но на удивление я смог снова загрузиться через несколько дней. Вчера он снова разбился.

 Boot Info Script e7fc706 + Boot-Repair extra info [Boot-Info 9Feb2015]   ============================= Boot Info Summary: ===============================   ============================ Drive/Partition Info: =============================  no valid partition table found "blkid" output: ________________________________________________________________  Device UUID TYPE LABEL  /dev/loop0 squashfs  /dev/sr0 iso9660 Ubuntu 12.04.5 LTS amd64  ========================= "ls -l /dev/disk/by-id" output: ======================  total 0 lrwxrwxrwx 1 root root 9 Jan 18 16:29 ata-MATSHITADVD-RAM_UJ8E2_S_H090_449177 -> ../../sr0  ================================ Mount points: =================================  Device Mount_Point Type Options  /dev/loop0 /rofs squashfs (ro,noatime) /dev/sr0 /cdrom iso9660 (ro,noatime)    ADDITIONAL INFORMATION : =================== log of boot-repair 2016-01-18__16h55 =================== boot-repair version : 4ppa35 boot-sav version : 4ppa35 glade2script version : 3.2.2~ppa45~precise boot-sav-extra version : 4ppa35 boot-repair is executed in live-session (Ubuntu 12.04.5 LTS, precise, Ubuntu, x86_64) CPU op-mode(s): 32-bit, 64-bit file=/cdrom/preseed/ubuntu.seed boot=casper initrd=/casper/initrd.lz quiet splash -- maybe-ubiquity ls: cannot access /home/usr/.config: No such file or directory  =================== os-prober:   =================== blkid: /dev/loop0: TYPE="squashfs" /dev/sr0: LABEL="Ubuntu 12.04.5 LTS amd64" TYPE="iso9660"   =================== UEFI/Legacy mode: This live-session is not in EFI-mode. SecureBoot maybe enabled.   =================== PARTITIONS & DISKS:    =================== parted -l:  Warning: Unable to open /dev/sr0 read-write (Read-only file system). /dev/sr0 has been opened read-only. Error: Can't have a partition outside the disk!  =================== parted -lm:  Warning: Unable to open /dev/sr0 read-write (Read-only file system). /dev/sr0 has been opened read-only. Error: Can't have a partition outside the disk!  =================== lsblk: KNAME TYPE FSTYPE SIZE LABEL sr0 rom iso9660 758M Ubuntu 12.04.5 LTS amd64 loop0 loop squashfs 712.6M  KNAME ROTA RO RM STATE MOUNTPOINT sr0 1 0 1 running /cdrom loop0 1 1 0 /rofs   =================== mount: /cow on / type overlayfs (rw) proc on /proc type proc (rw,noexec,nosuid,nodev) sysfs on /sys type sysfs (rw,noexec,nosuid,nodev) 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) /dev/sr0 on /cdrom type iso9660 (ro,noatime) /dev/loop0 on /rofs type squashfs (ro,noatime) 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) tmpfs on /tmp type tmpfs (rw,nosuid,nodev) none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880) none on /run/shm type tmpfs (rw,nosuid,nodev) gvfs-fuse-daemon on /home/ubuntu/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=ubuntu)   =================== ls: /sys/block/sr0 (filtered): alignment_offset bdi capability dev device discard_alignment events events_async events_poll_msecs ext_range holders inflight power queue range removable ro size slaves stat subsystem trace uevent /dev (filtered): autofs block bsg btrfs-control bus cdrom cdrw char console core cpu cpu_dma_latency cuse disk dri dvd dvdrw ecryptfs fb0 fd full fuse hpet input kmsg libmtp-1-2 log mapper mcelog mei mem net network_latency network_throughput null port ppp psaux ptmx pts random rfkill rtc rtc0 sg0 shm snapshot snd sr0 stderr stdin stdout uhid uinput urandom v4l vga_arbiter vhci vhost-net video0 zero ls /dev/mapper: control  =================== df -Th:  Filesystem Type Size Used Avail Use% Mounted on /cow overlayfs 3.9G 169M 3.7G 5% / udev devtmpfs 3.9G 12K 3.9G 1% /dev tmpfs tmpfs 787M 856K 787M 1% /run /dev/sr0 iso9660 758M 758M 0 100% /cdrom /dev/loop0 squashfs 713M 713M 0 100% /rofs tmpfs tmpfs 3.9G 32K 3.9G 1% /tmp none tmpfs 5.0M 4.0K 5.0M 1% /run/lock none tmpfs 3.9G 600K 3.9G 1% /run/shm  =================== fdisk -l:    Error: no partitions   =================== Suggested repair The default repair of the Boot-Repair utility would not act on the boot.   =================== User settings The settings chosen by the user will not act on the boot.     pastebinit packages needed W: Duplicate sources.list entry cdrom://Ubuntu 12.04.5 LTS _Precise Pangolin_ - Release amd64 (20140807.1)/ precise/main i386 Packages (/var/lib/apt/lists/Ubuntu%2012.04.5%20LTS%20%5fPrecise%20Pangolin%5f%20-%20Release%20amd64%20(20140807.1)_dists_precise_main_binary-i386_Packages) W: Duplicate sources.list entry cdrom://Ubuntu 12.04.5 LTS _Precise Pangolin_ - Release amd64 (20140807.1)/ precise/restricted i386 Packages (/var/lib/apt/lists/Ubuntu%2012.04.5%20LTS%20%5fPrecise%20Pangolin%5f%20-%20Release%20amd64%20(20140807.1)_dists_precise_restricted_binary-i386_Packages) W: You may want to run apt-get update to correct these problems dpkg-preconfigure: unable to re-open stdin: No such file or directory