If you want to defrag your drive, but you don't want the sceensaver to come on and yet you don't want to disable the screensaver in display properties, then try this:

Start the program that you don't want the screensaver to come on, and get a heavy enough object to press the SHIFT key down, that should prevent the screensaver from coming on. <img border="0" title="" alt="[Wink]" src="wink.gif" />

This should work in 95, 98 and probably ME, 2000 & XP as well.
Now just remember to take the object off the keyboard to avoid any unwanted surprises like accidentally opening several desktop shorcuts at once.