Originally Posted by matox
In Konsole Shell --> Edit --> I've press Reset & Clear Terminal. After that I can't execute any commands like cd, ls, or anything else.
I also can't see the line with my username.
It sounds like the Konsole config file is messed up. The konsole config file is at /home/user/.kde/share/apps/konsole. Take a look at the console config file and see if you can see what the problem is or you could post it here for other people to take a look at.
Most distributions keep a default .kde file tree in /etc. You could possibly find the default konsole config in /etc and copy it to /home/user/.kde/share/apps/konsole to restore the config to the defaults.
find /etc -iname "*konsole*"
If you copy the config file as root you will also have to change to ownership to user:groupname because the copy will set ownership to root:root.