I discovered I had a guest user account logged in when I tried to shut down and Lubuntu told me I couldn't. When I try to switch users from my administrator account to the guest account I am asked for a password. My friend, who had logged in as a guest, claims he did not create a password.
Ideally I'd like someone will tell me how to get into this guest account, but I will be satisfied if all I get is advice on the best way to shutdown and eliminate the guest account. Thanks!