What can cause a computer to come on by itself. It is shut down, not hibernated or sleeping and it comes on during the night by itself. No pets or kids or others that are doing it. I have Norton Internet security, and dial-up. I did notice that Norton has net detect set in task scheduler to check every four hours for a network, could that cause the computer that is shut down come back on? I have been turning off the power strip to ensure the computer stays off.