Restarting, Splash screen, Black Screen with login, no access

English Install/Boot/Login
#1

Greetings,

After installing kdf5 Disk Space utility, having done some adjustments in network serving restarted the system.
Sudenly after usual green splash screen with some boot option a black screen appears with:

Welcome to OpenSUSE Leap 42.1 - Kernel 4.1.27-27-default (ttyl)

Hint: Num lock off

linux-flw3 login:_ (blinking cursor)

My admin password is not beige accepted here. Simply cannot get acces any further.

I have newer used any password to log in in that stage. The system has always opened smoothly and then on KDE Plasma desktop there has been a prompt for admin password.

I have tried to restart the computer all in vain. The same logon prompt.

I will appreciate any prompt and helpful solution if any.
Thank you in advance,

OpenSuse Leap 41.2/KDE Plasma 5.2(?)

#2

After some tries I have discovered that if I insert my user and password I am probably taken to my home place:

ac@linux-flw3:~> _

At least there are some chance to use some magic commands.
But which, to get into?

#3

This means that ( at least ) one of your adjustments causes a failure in starting the X server, which is needed to run a graphical desktop. What you see now is the console.