Ah, recently, I've been unable to login to my main master account, as it would return me to the login screen after entering my password. Thinking I could just delete the account and make a new one, I logged in via the guest account, went to 'User Accounts' and authenticated with the main account's password. I was successfully able to delete the account, and create a new one. Once I returned to the login screen to log in with my new account, it asked for a password, though I hadn't set one. The old password does not work either. I returned to the guest account, went to 'User Accounts', to see that the Password field shows "Account Disabled" for my new account. Since I deleted my old account, I am unable to authenticate with the master password. I cannot add, change, or delete any accounts - nor can I login to it. Don't know what to do from here.
EDIT: Also, I tried changing to the textual login screen with Ctrl + Alt + F2, but my monitor reads "Input signal out of range - change settings to 1600x1050" or something to that effect.