System hangs on logout
From either KDE or Gnome GUI, system hangs after clicking logout from menus or applet icon. KDE screen stays blank. Gnome screen displays very colorful pattern; lines and characters, most with "~" over them... While hung, system does not respond to Ctrl-Alt-Del, but requires pushing reboot or shutdown buttons on the tower.
Fresh install of Debian Lenny on dedicated basic disk
Kernel: 2.6.26-2-686 #1 SMP
AMD Athlon 64 x 2 dual core processor 4600+
Have done: broad Google search and found similar complaints, no solution; Debian Users mail list with no response to question; search of linuxquestions.org with possible similar problems, no solution.
I would like to know how to set up tracking/logging of this process if no solution available short term.