Very often when I shut down the computer, Windows shuts down, the display goes black, but the computer itself does not switch off. Therefore I must do a manual hard shut-down by pressing the power button until the computer shuts down. This is a Dell 690 Precision Workstatiion Dual Xeon 5160 processor with Windows XP Professional. Dell says they have no case history of this happeing and can only recommending uninstalling everything and re-building the system. This would take me three days and I'm not convinced it is the answer. Do you have better suggestions?