screen saver

I have just begun streaming news from Australia and playing CDs on my
computer. Is there a way to turn off my screen apart from the controls for
these modes?

( I am pretty sure that before this, I had screen saving cut in and
deactivate the screen when I was not word processing.)

Now when I am listening to news or CD music, the screen stays on all the
time.

Wanting to extend the life of my computer and believe that the screeen is a
major wear and tear spot.
--
hedon