TO TURN OFF THE SLEEP & HIBERNATION MODES ON YOUR COMPUTER (Windows XP): 

Note: The Sleep Mode turns off the monitor and hard drive and reduces current to the Pentium chip or Pentium-like chip after so many minutes of non-use. This saves electricity and could prolong the life of your monitor, hard drive and other parts in your computer. The Hibernation Mode is a much deeper sleep mode, which saves even more electricity. It saves a snapshot of the "desktop" and all the programs you have open onto the hard drive, then shuts down the computer, leaving just a trickle current. Both of these modes can cause problems with your computer (for example, your computer may not start up again when you press a key or move the mouse), so we just turn them off at the expense of reducing the life of the hard drive and monitor.

1) Right-click on the “desktop” anywhere there is no icon. (The desktop is the main screen where you see the Recycle Bin, My Computer, My Documents, etc. icons.) 

2) Click on Properties

3) Click on the Screen Saver tab. 

4) Click on the Power… button. 

5) Click on the Down Arrow next to whatever is in the Power scheme box, then click on Always On.  

6) You should then see the settings under Plugged in change for Turn off monitor, Turn off hard disk, System standby [Sleep] mode [and Hibernation mode]. Be sure that the settings for all of these say “Never.” 

Note: You can change Turn off monitor to After 20 mins if you want to turn off your monitor to save electricity. The monitor will turn on again automatically when you move the mouse or press any key. This feature usually works without any problems.

7) Click on the Hibernate tab, then click to remove the check mark next to  Enable hibernation if there is one.

8) Click on OK

9) Click on OK

10) Close all open programs, then restart the computer for the new settings to take effect.