cannot log on as administrator even with correct password

i just cant log on , although my password is correct. How do i know that my password is correct? i tried to use an incorrect password and it says invalind password. i can only log on as a guest which doesnt have much authority? any suggestion? or fix?

otherwise I have to re-install again zorin

still no access. but i found something not riight, when i login to using ctrl alt f1, at the bottom it says "no directory, logging on with HOME=/"

I dont know what this mean

It means the location of you home has been changed to a location that no longer exists, or that you no longer have permission to access it.

Were you able to log into your account after switching to tty1 (ctrl+alt+ F1) ?

Run this and post your results

Code:

cat /etc/passwd | grep yourusername
ls -l $( cat /etc/passwd | grep yourusername | cut -d ':' -f 6 )/..
ls -l /home/
mount

and of course replace the "yourusername" with your actually username for the computer.
I'm sure this information will be very helpful in finding what is going on, and help us help you to fix the issue.

NOTE: Please note your password is NOT stored in the /etc/passwd file like may think it is, it is hashed and stored in /etc/shadow and you don't have access to read that file. (not without sudo or root anyway)

Also can you check at logon that your name is in the login box and not "Guest"