I tried something else: from my other PC I connected to the laptop via ssh. When the laptop freezes /home/rallo/.xsession-errors contains the following:
Xsession: X session started for rallo at So 4. Mär 16:27:07 CET 2007 startkde: Starting up... kbuildsycoca running... konsole: WARNING: Unable to use /usr/share/apps/konsole/mc.desktop konsole: WARNING: Unable to use /usr/share/apps/konsole/sumc.desktop konsole: WARNING: Unable to use /usr/share/apps/konsole/screen.desktop X Error: BadWindow (invalid Window parameter) 3 Major opcode: 19 Minor opcode: 0 Resource id: 0x2400005 X Error: BadWindow (invalid Window parameter) 3 Major opcode: 19 Minor opcode: 0 Resource id: 0x2400005 Ralph