My computer intermittently enters sleep mode, and there does not seem to be any reason for this behaviour. When the computer goes into sleep mode no frantic pushing of buttons is able to restore the computer from sleep, so I turn the computer off and on at the power point to restore operation. I have disabled all the sleep type options within the Power Options control panel, but the problem remains. Could it have something to do with the wireless keyboard and mouse connected to the computer? The computer is running Windows XP Service Pack 2.

It is possible that your computer is not entering sleep mode, but is instead entering hibernation mode, which is why you are unable to wake the computer by pressing keys on your keyboard. Sleep (or standby) mode is a lower-powered mode of Windows whereby the monitor is placed into standby mode (you may see an amber light appear on the monitor to indicate the monitor has gone into standby), copies all the contents of the current state of your PC (such as work in progress) into system RAM, and then stops the hard drives. In this state, your computer still needs to have some power consumption, to maintain the state of the PC which has been loaded onto RAM. As such, if you kill power to the computer while in standby mode you will lose any unsaved work, as the work has been saved into RAM which is volatile storage (meaning when power is cut, anything stored in RAM is lost). In contrast, hibernation mode copies the current state of your computer onto the hard drive and then completely powers down the computer. This means you can completely disconnect power from the computer while in hibernation, as the current state of the PC has been copied to hard drive (non-volatile storage, which does not require power to retain its memory) and the computer is technically completely powered-down during hibernation. When the computer is in hibernation the only way to wake the machine is by pressing the power button on the computer, much like you would when starting the computer from a completely cold shutdown. It is possible that your computer has gone into hibernation mode, and this is why you cannot wake the computer using the keyboard or mouse. Next time this happens, try pressing the computer power button to see whether this will restore the computer.

If your computer is going into hibernation mode, we need to disable this behaviour. Go into the Power Options control panel and click the “Hibernate” tab. Untick the option “Enable hibernation” and click “Apply”. Then, go to the “Advanced” tab and for the option “When I press the power button on my computer” select “Ask me what to do”. Click “Apply” and then OK. This should disable hibernation on the computer. Check whether the problem persists.

Another potential reason for this problem does relate to the wireless keyboard and mouse which is connected to your computer. Many such keyboards and mice have special function keys, which allow you to put the computer into standby or hibernation mode by simply pressing one of these keys. If you do not have the correct drivers installed for your wireless keyboard or mouse this could be causing problems, as the computer may be unable to properly understand and interpret certain keystrokes which you enter into the keyboard. As such, when you enter a particular key (or combination of keys) the computer may think those keystrokes are to place the computer into standby or hibernation mode. Therefore, make sure you have the correct drivers installed for your wireless keyboard and mouse. These can usually be found on the manufacturer’s website for this equipment.

For the moment, putting aside why the computer is entering the standby or hibernation mode, if your computer is going into standby mode then you should be able to wake the computer using the keyboard or mouse. However, users have reported that using USB wireless devices to bring a computer out of standby can present problems, as sometimes the computer does not provide enough power to the USB receiver during standby to accept commands from the wireless devices. Therefore, the computer cannot receive any commands or keystrokes from the wireless keyboard or mouse, and cannot bring the computer out of standby mode. Go to the “Start” menu > “Control Panel” and open the “System” control panel (you may need to first click the “Performance and Maintenance” category). In the window that appears, click the “Hardware” tab and the “Device Manager” button. Expand “Keyboards” and locate the wireless keyboard device connected to your computer. Right-click on the device and select “Properties”. In the properties window for the keyboard device, click the “Power Management” tab. Disable (untick) “Allow the computer to turn off this device to save power” as we do not want this device to be turned off to save power, otherwise it may not wake the computer from standby! Enable (tick) “Allow this device to bring the computer out of standby” as we want this device to have the ability to wake the computer. Once this is done, click OK. Expand “Mice and other pointing devices” and open the properties for the wireless mouse connected to the computer. Repeat the same procedure as for the wireless keyboard, to ensure the device is not turned off and that the device can wake the computer from standby mode. Click OK. Next time the problem occurs, check whether the keyboard and/or mouse can restore the computer from standby mode.

Even if the keyboard and mouse can restore the computer, this only allows us to restore the computer from standby and does not eliminate the computer from randomly entering standby mode. Should you still have the problem of the computer entering standby or hibernation mode without cause, we need to investigate whether a program or process running in the background could be conflicting with the computer, causing this behaviour. Restart the computer, so all startup programs and processes load, and once the computer has finished booting, immediately close any programs or processes which you are able to close (e.g. in the system tray or programs which are visibly running in the task bar). Once this has been done, press CTRL-ALT-DEL to open the Windows Task Manager. Click the “Processes” tab. This will show you all the processes which are currently running on the computer. Click the “User Name” heading to sort the processes by user name (if this is not visible, go to the “View” menu > “Select Columns” and tick “User Name”. Close all processes running under your user name, except ?explorer.exe? (the Windows graphical interface) and ?taskmgr.exe? (the Windows Task Manager, which you are currently using to close the processes). Once these processes have been closed, leave the computer and see whether it goes into standby or hibernation mode under its own accord. If not, then one of those programs or processes was causing the problem. You now need to go through a process of elimination to determine which of the processes was causing the problem. I would suggest restarting the computer, and then closing the processes one-by-one, each time waiting to see whether the problem occurs to determine whether that program or process was the cause.

If the problem occurs even after closing all programs and processes running on the computer, the next potential catalyst for the problem could be peripheral devices which are connected to the computer, such as printers and scanners. Disconnect all peripheral devices from the computer. I suggest that you even disconnect your wireless keyboard and mouse, and instead (temporarily) connect a corded keyboard and mouse to the computer. Once this has been done, and you only have essential devices connected to the computer (i.e. monitor, keyboard, and mouse) restart and check whether the problem persists. If the problem does not occur, then manually reconnect the devices one at a time, each time waiting to see whether the problem occurs.

If you have tried closing processes and disconnecting peripheral devices, but the problem continues, please contact me again for further advice on resolving this tricky issue.