If you have purchased or built a new computer in the last few years, you might be aware of the switch from traditional BIOS software to UEFI. What you might not be aware of is that this can cause your Ubuntu installation to fail unless your disk is partitioned correctly.
If the hard drive you are attempting to load Ubuntu onto is loaded as an EFI drive, you will need to add an extra partition to properly install Ubuntu. You will need a partition at the front of the drive, formatted in fat32, and between 100MB and 250Mb. Mount this partition as /boot/efi. You must also be sure that you are running a 64bit OS, as the 32bit version will not detect EFI.