Windows XP uses a default power scheme that helps conserve energy. A typical default setting is for XP to turn off your monitor after 20 minutes of inactivity. You can turn the monitor on again by simply moving your mouse. If you want to stop this behavior or adjust it, you can easily do so.
To adjust power options, just follow these steps:
1. Click Start--> Control Panel.
2. Double-click--> Power Options.
Note: If you don't see Power Options--> you need to click the Switch to Classic View option in the left Control Panel pane. Then, you'll see the Power Options.
3. On the Power Schemes tab--> you can change the monitor and hard disks turn-off value. You can also use the Power Schemes drop-down menu and choose a different scheme that might work well for you. The schemes simply pre-configure the monitor and hard disks turn-off features, but you can manually change them to whatever you want.
4. Click OK to save your changes.