I have Ubuntu 18.04 LTS running on an HP 2540P laptop and it is working very well.
However, I have noticed that if a wrong password is entered followed by a second
login attempt with a correct password, that Ubuntu fails to load. The second login
attempt looks to be loading then the screen goes dark and blank and never recovers;
the computer has to be powered down to recover.
Watching the hard drive activity light shows not activity after the screen goes blank.

I'm sorry if this question has already been asked; I'm new to this forum and this is my first post.