Step #1: Log in to the system as the "root" user.
Step #2: For this example, let’s assume the username is "fred".
To find the process(es) that are associated with that user, type "ps -u fred". At least one process should be listed for that user.
The output from this command might look like this:
PID TTY TIME COMMAND 348 i1e 0:02 sh
Step #3: If that user has not logged in anywhere else, it should be safe to kill their process(es).
To kill the "hung" process, type "kill -9 348". (348 is the Process ID number).
Step #4: The terminal should now be unlocked. Hit the "<Enter>" key at that terminal several times to check.