Our PC is haunted! It has suddenly started switching itself on at strange times of the day and night. I have checked all the Power Management options, but the problem continues. The computer is running Windows Me.

You will be glad to hear that it is unlikely your computer is haunted, but instead there is a misconfiguration in the BIOS power management settings. There are power management options in Windows (in the Power Management or Power Options) control panel, but these do not control the automatic power-up of the computer. However, there are power management settings in the computer BIOS. The BIOS is the basic input output system which controls the very low-level functions of the computer, in particular recognising all of the computer hardware (e.g. memory, hard drives) and prepares the computer for basic operation before handing control to the computer operating system (Windows). There are often settings within the BIOS which allow the computer to wake on certain events, such as Wake on LAN (when the computer receives data over the network connection), Wake on USB (when the computer receives input from a USB device), Wake on Modem (when activity is detected on the computer modem, most useful for automatically starting the computer to receive a fax), etc. It is likely that one of these settings is enabled, resulting in the computer automatically starting itself.

To resolve this problem, you will need to enter the computer BIOS setup. Restart the computer and during the POST (power-on self-test, when all the memory tests and hardware detection appears, before the Windows splash screen appears) a message should appear saying something such as ‘Press DEL to enter setup’. The exact key will differ depending on your computer motherboard, but press the nominated key to enter the setup. The BIOS setup should appear on the screen. Be aware that this is a sensitive part of the computer, and any incorrect modification of settings could make the computer unbootable, so do not change any settings unless you are certain about the changes which are being made. With this disclaimer out of the way, try to locate the Power Management section of the BIOS setup. Once found, look through the configuration for any settings which may be causing the computer to automatically start, particularly any Wake on … settings. If you wish to change any settings, write down their current values (in case you need to reverse the change at some point in the future) and change the setting. After you are finished, Save and Exit the BIOS setup. Hopefully, the computer should no longer start of its own accord.