[ubuntu] Unable to login after kernel update today

I have an Ubuntu 15.10 machine that has been ruing fine for Months. This moing I ran the updates and the only thing I saw was a keel update. There could have been something else, but the keel is all I saw. The update seemed to run fine, but upon reboot I am presented with the login screen. I should note here that this is a single user machine into which I am auto logged in. Anyway, on this login screen I see three users named "Comment", one "Samba Guest", and one "Guest". Samba Guest, and Guest are supposed to be disabled, and my user id is NOT one of the selections. Of the three "Comment" users, two have the default Ubuntu purple background, and one has the desktop image from my userid. However, NONE of them will accept my password, meaning they all report it as invalid.

I can do a Ctrl-Alt-F1 and get a terminal window that I can use my userid and password to login with. but I just don't know what to do from there. I am using a different machine to enter this post and so caot get a screenshot or log files from the other one.

Any help is appreciated, including help on where to look to find out what has gone haywire.

And one last question before I go, is there any way to upgrade the machine to 16.04 from the terminal command line? I have been considering upgrading for a couple of weeks now so this might be a good time if I can do it.

Thanks,

Wayne

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