How do I remove Xfce completely

I believe there are some components of xubuntu-desktop that are mutually exclusive with ubuntu-desktop. My first suggestion would be to reinstall the ubuntu-desktop package to see if this clears up your problem.

Thanks for that. Unfortunately it made no difference but I'm now sure that the desktops are not actually being deleted, I tried booting after removing both ubuntu-desktop and xubuntu-desktop and still got the same login screen. I've since tried logging in under both Ubuntu and Xubuntu, and they're still there.

But you can remove it like next;
1- Install PackageKit for easy instructions: Go to Synaptic and install packagekit and in the window accept additional libraries to be installed .
2- Run it , and then in that window , go Desktop Environment ; unchech Xubuntu Desktop Enviroment , and click apply ; it'll be removed , now , you can remove packagekit using synaptic.

Good Luck ;)

Try this: Copy into the terminal

sudo apt-get remove a2ps abiword abiword-common abiword-plugins gnumeric-common gnumeric-gtk gtk2-engines-xfce imagemagick libaiksaurus-1.2-0c2a libaiksaurus-1.2-data libaiksaurusgtk-1.2-0c2a libexo-0.3-0 libgdome2-0 libgdome2-cpp-smart0c2a libglib2.0-data libgoffice-0-6 libgoffice-0-6-common libgsf-gnome-1-114 libgtkmathview0c2a liblink-grammar4 libots0 libt1-5 libtagc0 libthunar-vfs-1-2 libwpd-stream8c2a libxfce4mcs-client3 libxfce4mcs-manager3 libxfce4util4 libxfcegui4-4 link-grammar-dictionaries-en mousepad mozilla-thunderbird orage psutils python-exo ristretto tango-icon-theme tango-icon-theme-common thunar thunar-archive-plugin thunar-data thunar-media-tags-plugin thunar-thumbnailers thunar-volman thunderbird vim-runtime xfce4-appfinder xfce4-battery-plugin xfce4-clipman-plugin xfce4-cpugraph-plugin xfce4-dict-plugin xfce4-fsguard-plugin xfce4-governor-plugin xfce4-icon-theme xfce4-mailwatch-plugin xfce4-mcs-manager xfce4-mcs-plugins xfce4-mcs-plugins-extra xfce4-mixer xfce4-mixer-alsa xfce4-mount-plugin xfce4-netload-plugin xfce4-notes-plugin xfce4-panel xfce4-places-plugin xfce4-quicklauncher-plugin xfce4-screenshooter-plugin xfce4-session xfce4-smartbookmark-plugin xfce4-systemload-plugin xfce4-terminal xfce4-utils xfce4-verve-plugin xfce4-weather-plugin xfce4-xkb-plugin xfdesktop4 xfdesktop4-data xfprint4 xfwm4 xfwm4-themes xubuntu-artwork-usplash xubuntu-default-settings xubuntu-desktop xubuntu-docs && sudo apt-get install ubuntu-desktop

This is from the tutorial: http://www.psychocats.net/ubuntu/puregnomehardy

Thanks for the suggestions, unfortunately I had problems with both :

1. I couldn't find Packagekit in Synaptic.

2. Ran the long script from psychocats and got the error message 'Package libwpd-stream8c2a is not installed, so not removed E: Couldn't find package libxfce4mcs-client3'

Regards
Kevin

What version of Ubuntu are you running? If you are unsure, open a terminal and execute:

   lsb_release -a

It is 9.04 jaunty.

OK , simply do this.

sudo apt-get remove xubuntu-desktop

Good Luck ;)

Tried that and it said 'Package xubuntu-desktop is not installed, so not removed'

If you ran the large command above, everything from xfce should be gone. If you now run:

  sudo apt-get install ubuntu-desktop

It should restore the regular ubuntu desktop.

Tried that and it said 'ubuntu-desktop is already the newest version'.

Ok, so if I read all this correctly, all we're trying to do is set the login screen back to the Ubuntu default?

System>Administration>Login Window>Local select your desired login screen.

Well that got rid of the blue log-in screen but it's still taking forever to boot up. I'm thinking that it maybe easiest to to reinstall the o/s?

At this point, probably. Be sure to back up everything you want to keep from your /home directory, and any configuration files that you modified, so that it's easy to restore your previous setup.