Windows XP

Click the "start" button located in the lower left corner of the screen. Select the link "control Panel". The control panel is used to change various settings of Window XP.
In the classic start menu, double-click power options. If you start" categories, select "Performance and maintenance, power options. On the tabs in the "power options Properties" you can control the power settings of your screen and hard disks and to configure the Uninterruptible Power supply if you have one.
Select the tab "power Schemes" section of the "Home/desktop". Select "Never" for "display off" and "Disconnect drives" . Click "Apply" and then click "OK".
Windows 98/ME/2000 Windows 98/ME/2000

Click the "start" button, select "control Panel" and find "power Management or power options icon in the control panel settings.
Select "power Scheme" tab, if it is not already selected. From the drop down menu called "Disable monitor", select "Never". Click "Apply" and "OK".