When it got me the black screen with the Ok's it take more time than usual. Then I turn off the computer and now I am stuck with the screen before showing the login screen.
Press any button to show the text messages. If that does not help, hold the shift key before Kubuntu starts booting. You will get into the GRUB boot loader. Edit the the command line and remove silent and splash. That way, you can see all the messages. Maybe you will see the problem then. – queueoverflowFeb 2 at 13:49
silentandsplash. That way, you can see all the messages. Maybe you will see the problem then. – queueoverflow Feb 2 at 13:49