Duplicated on Kubuntu 10.04. Running KDM with either KDE or fluxbox results in blank screen on logout (exit) from X session. SSH from another computer reveals that Xorg is at 100% cpu. Kill xorg followed by sudo /etc/init.d/kdm restart from ssh will get you back up and running. Removing nvidia proprietary drivers (version 96 in this case with an older 440MX AGP card) eliminates the issue.
Duplicated on Kubuntu 10.04. Running KDM with either KDE or fluxbox results in blank screen on logout (exit) from X session. SSH from another computer reveals that Xorg is at 100% cpu. Kill xorg followed by sudo /etc/init.d/kdm restart from ssh will get you back up and running. Removing nvidia proprietary drivers (version 96 in this case with an older 440MX AGP card) eliminates the issue.