How to Troubleshoot the Windows XP Sleep Mode

1. Click Start > Control Panel > Performance and Maintenance > Power Options. Select a power scheme that suits your energy saving needs. Under 'Settings' select whether you'd like to turn off your monitor or hard disks after a certain amount of inactivity. Also choose whether you'd like the computer to enter standby or hibernation mode when it isn't in use. Select 'Save As,' enter the desired name and click OK.
2. Navigate to the website of your computer's manufacturer. Search on your computer's model number to find your driver updates. Download and install all updates that your computer needs, especially those for the video and sound devices. Also look for updates for outdated third-party software that is installed on your computer.
3. Flash your system BIOS with the most recent update. To get the update file, navigate to your computer manufacturer's website. Download the correct BIOS update file for your model. Get a blank floppy disk or burnable CD. Check the documentation that came with the BIOS update file for specific instructions for on how to create a flash disk for your computer. Use the BIOS update file to create a bootable disk. Restart your computer with the disk in the drive. Remove the disk from the drive and restart your computer to boot Windows.
4. Close any open programs that run active content such as music, video or animated advertisements before you leave your computer. These programs may prevent your computer from entering standby mode, since when they're running, Windows does not consider your computer to be inactive. Programs that run active content include Windows Media Player, Internet Explorer windows which contain animations or streaming media, active virus scanners and backup utilities.
5. Unplug devices that are connected by USB or FireWire prior to bringing your computer out of standby. Plug them back in once the computer is active again.
6. Shut down your computer by depressing the power button if it won't wake up from sleep mode. Leave it off for a full 30 seconds, then turn it back on again. If the computer will not shut down when the power button is pressed, press and hold the power button for 10 seconds.
7. Check the documentation of your peripheral devices, mouse and keyboard to see if they support sleep mode. Older devices may not be able to go on standby with the computer, and can cause the sleep mode to stop functioning over time. Replace these obsolete devices with ones that are capable of entering standby.