It goes like this:
Ubutu 14.04 LTS
I keep it fairly up to date. Usually allow updates when nagged. Was nagged this morning and allowed update. Rebooted. Got a message that something failed. Assumed it was because my /boot was full (again!). Used a procedure that I have used many times to purge old kernel and related files to reclaim space. Assume I over-reclaimed". Ran updater again. It then said I had to reboot. Allowed reboot. Nothing there but air.
I am now running from the original install CD (try ubuntu option). Installed boot-repair but it is stuck on "Purge kernels then reinstall last kernel sda6 (ins). This may require severlal minutes"
Then I installed boot-info and created a report here: