Won't recognize password

Above when you could not log in to Debian Wheezy after installing, I don't think you understood what you were doing wrong. The very first login prompt looks almost identical to the one you gave the screen shot of prompting that you input the incorrect password.
If you input your password in that login screen instead of your username, no matter what you enter on the next screens, you will receive the password incorrect screen you posted. This is the login screen where you input your user name:



In that screen you must input the username you set up when installing. The next screen will be where you should enter the password. Notice it looks almost identical to the previous "login" prompt.



If you input either the username or password incorrectly you will then get the password incorrect prompt you posted. If you only got the password wrong typing it correctly here will still get you in, but if you messed up the username or typed the password at the login prompt, it will not matter what you type here, it will never work. The solution is to click "cancel". that will return you to the original "login" prompt where you can re-enter your username.

It is a stupid arrangement, and we all have made this mistake countless times, even after knowing what we should do. It would have been better if the prompt said "user name" instead of "login" or if the prompt screen showed both input fields for the user name and password at the same time on one screen.

Thanks Todd for your patient reply, got it now, sorry for not picking up this simple error.
I'll do the re-installs and should be right now.

Tommy, my PC is a UEFI running in Legacy mode. I hope it'll work. I seem to remember some issues re UEFI in the Mint 19.3 release notes..