Hi Hanak,
we already did the work you said, but that was not effective.
And we find another symptoms.
when i read the creo model/drawing files in local(the file i stored in my HDD), the graphics is fine.
in this situation, i just open the other files from windchill cabinet or workspace, all of files in session is being to crash.(whatever it opened from local or Windchill commonspace/workspace)
so i think it is not about H/W or Drivers problem. i think it causes from Windchill server or vault.
we logged the case to the PTC TS yesterday night and they said to me give the Windchill log files.
thanks
pwj