unable to boot Lion because "Guest" login appears and wants a password which I don't have
Just type in your normal username and password.
Thanks for your reply. My problem is that I cannot get rid of the "guest"
login or alter the screen in any way.
Reinstall Lion (preferably from your TM backup). It doesn't take long.
I reinstalled Lion and the sign on was "guest" again! Frustrated I went through the whole process again and finally I got my sign-in screen.
The next thing I did was to disconnect the "guest" log-on.Thanks for your help.
Richard