I had upgraded ubuntu to 18.04 and now I have a very major problem on my laptop: I cannot login at all. The computer is a dell with ubuntu installed by the manufacter some years ago and the preceding upgrades went ok.
What happens is the following: The boot sequence goes ok until I reach the state of putting my password. The password is recognized but then nothing happens. The laptop is in a state of stasis and absolutely nothing happens for minutes on end.
There is no apparent possibility to change to another window manager that is less dangerous and so my laptop is not usable and if I do not find a way out my data are lost. What options are possible in that situation.