I've successfully run Ubuntu 12.04.01 on a partition on an older Acer laptop with Vista as the original OS, which still was accessible, until I, against my better judgment, acceded to the continual prompts to upgrade to 14.04.01 LTS, and did so last week. Took hours, as warned, but proceeded without any problems until the final prompt to restart computer. What appeared, after selecting Ubuntu on the OS page, was a black screen with lavender borders followed by a black screen with the following in command line font ( I'll abbreviate for brevity):
FOUR LINES OF mount: mounting
FOLLOWED BY /dev/loop0 on /root failed: Invalid argument
THEN /dev on /root/dev failed: No such file or directory
THEN /sys on /root/sys failed: No such file or directory
THEN /proc on /root/proc failed: No such file or directory
THEN NEW LINE Target filesystem doesn't have requested /sbin/init.
NEW LINE No init found. Try passing init+ bootarg.
NEW LINE BusyBox v.1.21.1 (Ubuntu 1:1.21.0-1ubuntu1) built-in shell (ash)
THEN Enter 'help' for a list of built-in commands.
THEN (initramfs)
AND CURSOR.
Nothing I've tried has succeeded, and not only am I unable to get 14.04.01 LTS to work, but I am also unable to get Vista to boot, or even go into any repair mode. Wouldn't bother with this, except I have vital data in the old LTS that I didn't back up externally. Sorry for the length of question - I'm no novice, but at wit's end. I don't expect my patients to define the parameters of the surgeries I perform, but I take extensive histories, in addition to performing extensive physicals, before I do anything, as is true in analogy for my biotech clients, so for the true Ubuntu experts & developers, please forgive the exactness of my question.