Cannot recover laptop

I have a 64bit laptop on which I installed Mint 20. I have been using it for about a week, I now get the message "unable to launch Cinnamon-Session-Cinnamon" X Session --- "Cinnamon-Session-Cinnamon" not found; Falling Back To default Session. I had a look in the forums and tried the Ctrl-Alt F1 method but when the Login prompt came up it also asked for a password. I use the same password for all things Linux so I know it's correct the login passes but the password does not, just comes back :login incorrect" Is there any other way that I can recover the laptop? Thanks in advance.