The massive but! - It will boot with a Ubuntu CD in the drive, but boots to the regular install of Ubuntu not the Live CD.
Very weird, I'm dual booting Windows 8 and Ubuntu 12.04 on an Asus X550C
Last night several updates ran and upon rebooting Ubuntu gets to just past the Grub loader and stops there, on the dark red screen but before the Ubuntu name is shown.
I tried Boot Repair and it hasn't worked for me.
I tried going into the computer Bios to set booting to CD but it's not an option in the boot menu anymore.
Boot Repair put this up - http://paste.ubuntu.com/7694285/
Any help would be massively appreciated
EDIT - I checked GParted after reading this
The boot files of [The OS now in use - Ubuntu 12.04.4 LTS] are far from the start of the >disk. Your BIOS may not detect them. You may want to retry after creating a /boot >partition (EXT4, >200MB, start of the disk). This can be performed via tools such as >gParted. Then select this partition via the [Separate /boot partition:] option of [Boot >Repair]. (https://help.ubuntu.com/community/BootPartition)
But it shows the boot partition at the start of the disk.
Update - In reply to the question "What happens if you boot an old kernel" - Same result