I've just installed DSL and all seemed to go fine. I logged in as root and went through the X setup. All was working well so I exited to the login prompt. However, all I got was a blank blue box about the size of a photo.

I seem to have to hard boot to get out of this then the superblock becomes corrupt.

Suggestions?

1) file system corrupt - #/sbin/shutdown -F -r. This will try and repair the filesystem and the superblock and this woud be taken care of.
2) I am not really sure why you were not able to go to the cli screen. What I can suggest is (a) edit /etc/inittab and put it on single user mode and see if the cli is coming up properly. If that works good then look for some gui tools to change the screen resolution to something lower and then check and see what is the best you can get.
Hope this helps.

Thanks for the reply. After struggling with this for a long time, I'm not sure I've made any headway. This may be partly due to that fact that I don't know what I should expect.

1) That seems to have worked. For now I don't exit to a prompt but rather I logoff using the restart option.

2) Booting to CLI is fine. When I go to run level 5, I get a ChUI login. That may be normal for DSL but I was expecting a GUI login. Changing the resolution does not seem to make a difference but if I use less than 1024 X 768 only about 50% of my screen is used. The interesting part is that when I log in as a user for the first time, it goes through the setup and then the WM works. As I said, when I logoff there is no login prompt but rather what appears to be a blank screen in a resolution of 800 X 640 (is this an attempt to use a GUI login?). Now the plot thickens. When I log in subsequent times, the WM fails because it gets a fatal error (106) trying to connect to the Xserver. However, this does not happen if I log in as root. The WM comes up fine. That seems to imply some kind of permissions error but that does not make sense because it did come up on the first login.

Does any of this suggest where the problem lies?

Well the shutdown was done to repair the file system (man poweroff).
I have not worked with DSL but then what might help here is creating a new user. What happens is the default settings would be given to the new user. That will help in the screen resolution part.
As far as the WM is concerned - I just hope you did not log in as a root and make any changes. But then ideally _most_ WMs have an option to click on some icon and change the WM and the way it is displayed.

Well the main screen configuration file is /etc/X11/xorg.conf. BACK UP THIS FILE. You can then correct the file where you have screen resolution and I think you should be good.

Maybe that is the problem. There is no xorg.conf. At least not in the /etc/X11 tree.