Obrigado pelas explicações @druidaobelix.
Caso eu tivesse selecionado a opção UEFI, ao invés de CSM, quando desabilitei o Secure Boot para realizar a instalação do Ubuntu teria dado certo? De qualquer forma, seguem os dados para os comando que você citou:
sudo fdisk -l
ubuntu@ubuntu:~$ sudo fdisk -l
Disk /dev/ram0: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram1: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram2: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram3: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram4: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram5: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram6: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram7: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram8: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram9: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram10: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram11: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram12: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram13: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram14: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram15: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/loop0: 1.1 GiB, 1186353152 bytes, 2317096 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 /dev/sda: 931.5 GiB, 1000204886016 bytes, 1953525168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 1AE3DC76-040F-4F20-92EC-F0DF4F7AEF27
Device Start End Sectors Size Type
/dev/sda1 2048 1023999 1021952 499M Windows recovery environment
/dev/sda2 1024000 1638399 614400 300M EFI System
/dev/sda3 1638400 1900543 262144 128M Microsoft reserved
/dev/sda4 1900544 1079332112 1077431569 513.8G Microsoft basic data
/dev/sda5 1079332864 1081012223 1679360 820M Windows recovery environment
/dev/sda6 1081012224 1500440575 419428352 200G Microsoft basic data
/dev/sda7 1500442624 1756028927 255586304 121.9G Microsoft basic data
/dev/sda8 1919870977 1951426560 31555584 15G Windows recovery environment
/dev/sda9 1951426561 1953523712 2097152 1G Windows recovery environment
/dev/sda10 1756028928 1767747583 11718656 5.6G Linux swap
/dev/sda11 1767747584 1768333311 585728 286M Linux filesystem
/dev/sda12 1768333312 1919870975 151537664 72.3G Linux filesystem
Partition 8 does not start on physical sector boundary.
Partition 9 does not start on physical sector boundary.
Partition table entries are not in disk order.
Disk /dev/sdb: 3.8 GiB, 4039114752 bytes, 7888896 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
Disklabel type: dos
Disk identifier: 0x000696c9
Device Boot Start End Sectors Size Id Type
/dev/sdb1 * 62 7881749 7881688 3.8G b W95 FAT32
sudo parted -l
ubuntu@ubuntu:~$ sudo parted -l
Model: ATA ST1000LM024 HN-M (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 1049kB 524MB 523MB ntfs Basic data partition hidden, diag
2 524MB 839MB 315MB fat32 EFI system partition boot, esp
3 839MB 973MB 134MB Microsoft reserved partition msftres
4 973MB 553GB 552GB ntfs Basic data partition msftdata
5 553GB 553GB 860MB ntfs hidden, diag
6 553GB 768GB 215GB ntfs Basic data partition msftdata
7 768GB 899GB 131GB ntfs Basic data partition msftdata
10 899GB 905GB 6000MB linux-swap(v1)
11 905GB 905GB 300MB ext2
12 905GB 983GB 77.6GB ext4
8 983GB 999GB 16.2GB ntfs Basic data partition hidden, diag
9 999GB 1000GB 1074MB fat32 Basic data partition hidden, diag
Model: Kingston DataTraveler 2.0 (scsi)
Disk /dev/sdb: 4039MB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:
Number Start End Size Type File system Flags
1 31.7kB 4035MB 4035MB primary fat32 boot
Warning: Unable to open /dev/sr0 read-write (Read-only file system). /dev/sr0
has been opened read-only.
Error: /dev/sr0: unrecognised disk label
Model: TSSTcorp CDDVDW SU-208FB (scsi)
Disk /dev/sr0: 710MB
Sector size (logical/physical): 2048B/2048B
Partition Table: unknown
Disk Flags:
1) Por falar nisso, qual é mesmo o hardware do seu computador?
Processor: Intel(R) Core(TM) i7-4510U CPU @ 2.00GHz 2.60GHz
RAM: 8Gb
System type: 64-bit OS, x64-based processor
Marca: Samsung-NP270E5J
Caso seja necessário algo além é só falar que informo aqui. Será que há um jeito de corrigir, sem ter que formatar/recuperar o disco?