Pc hanging after "log off"

I have an odd problem with my Fujitsu Siemens Scaleo 600, XP-Home SP2, after
a new clean XP Home re-installation.

When user is trying to log off "Start/LogOff", the PC screen goes randomly
into black (not every time) and I cannot longer make contact with it. Even
keyboard is not reacting (NumLock and CapsLock). But some how the PC is
still up running, because I can se the harddrive light flashes every now and
then! The only way to connect again is to push the power button until the PC
reboots again.

If using Win and L button, the PC is back on the "Logon screen" and there is
no problem logging on again.



I never experienced this before I took this clean XP re-install, so guessing
this has to be some settings or driver problem?



In the beginning I thought this problem were related to my GeForce4 Ti 4200
graphic card, so I tried the driver which I used before and are now running
the latest driver, but still the same.



My screensaver setting are:
Screen saver:
Wait 40 minutes on resuming, display Welcome screen

Screen saver/Power Option properties
Turn off monitor Never
Turn off hard disk Never
System standby Never

.....Advanced:
Prompt for password when computer resumes from standby.

Is there anyone out there to give me some advices or tips on what to do
now??



Kindly regard,



Pvest