[wlug] hosts file

Hi After playing with my networking settings in Breezy, I seem to have lost some data from my /etc/hosts file. Partly it requires editing to add to add "ubuntuDavid" to it. However without it I can't log in as root to edit it. Can't find password! I can't edit it with Knoppix, I don't have permission. Is there any way to edit it or is it a reinstall job. As it is I can't connect to the net or anything requiring root privilege. Thanks David Bowen