Warty to Hoary upgrade

[Keith Powell]

I have tried upgrading from Warty to Hoary by replacing "warty" with 
"hoary" in the apt sources list (as it says in the Unofficial Starter 
Guide). I then did a sudo apt-get dist-upgrade and it downloaded and 
installed about 500Mb. (I can't remember the exact amount).

It will boot into GDM normally. I enter my name and password as usual, 
and a small box appears with a light bulb and an OK button. I select 
the OK button and it takes me just to a terminal in the corner of the 
screen. The rest of the screen is black. I exit the terminal and it 
takes me straight back again to GDM! Even if I enter something like 
startx, or gnome in the terminal, I still just go back to GDM!

One other thing, selecting Gnome failsafe takes me to a black screen 
with a panel at the top, but there is nothing at all in the 
Applications menu - it's empty!

Please, what is the cause of this and how on earth do I get to the Gnome 
desktop? Warty works splendidly.

Many thanks to anyone who can sort this problem out. It's got me 
completely baffled!  

Cheers

Keith