Upgrade 10.10 fail. Black screen Gnome.

[kirkface8]

Yesterday I attempt to use update-manager to do a distribution update.
all was going good. i went to the kitchen to get a coffee and returned to a black screen with no cursor. the install couldnot have finished as it was still downloading updates i believe.

on reboot gnome did not respond so my last resort was to use kde for the time being. by running update-manager through kde I successfully updated to ubuntu 10.10. After completion of the update i restarted and gnome still had a non respinsive black screen on login.

Kde is still working fine.

How can I fix this?
Or at least how can I completely reinstall gnome.

Thanks

[kirkface8]

solved
by entering

sudo apt-get install --reinstall ubuntu-desktop

solved this by obviously reinstalling gnome.