As you said you do have a wonderfully configured Ubuntu in your guest account. This means that all your issues come from broken settings in your main account.
If Ubuntu runs as a virtual machine in Virtual Box create a snapshot before you proceed to be able to revert to the present state in case something went wrong.
To get a functioning administrator user back simply create a new user:
sudo adduser <name> --ingroup sudo
You will immediately be asked for a new UNIX password (nothing will be displayed while typing) and other data.
Log into the new account to see whether everything is to your liking.
This new user will have a name different to your previous account but you can use this new administrator account for clean up that follows below.
The safe way:
From another administrator account (see above) delete your broken user account (assuming dess
was the name)
sudo deluser dess
This will keep the home directory. Then rename the HOME directory to keep all the data we still need.
sudo mv /home/dess /home/dess.old
Now we can re-create our administrator dess
sudo adduser dess --ingroup sudo
Log in to your new account and hopefully be happy with it. All your data are still in the /home/dess.old
directory waiting for you to copy them over to your new account. If all is back you can safely delete the old directory to free space.
The fast and courageous way
As it were only settings that broke your account you may just delete them but keep your data in your HOME directory.
From a TTY terminal of another account delete all hidden dot files and directories (choose ls -a
to see them):
ls /home/dess -a ## just to make extra sure this is the right directory ##
sudo rm -Rf /home/dess/.* ## !!! please no extra blanks or typos here !!! ##
The last command is potentially dangerous as it can recursively and irreversibly delete all and everything (which would not be such a good idea on any other path).
Log in to your account to find everything working and the system magically re-create the dot files for your settings (now with better values). If anything went wrong you can just restore from your snapshot.
The desirable way
In the best case we would remember which settings we had changed and only deleted those setting files affected. But from what I read in your questions this may be too late at this point.