if i try to change/test a screensaver.
the program stops responding, rest of the computer works fine.
I have a 2008 MBP (13", 2.26 ghz, 2 gb ram, leopard) which freezes if i leave it idle for more than 2 minutes.
The screen goes black and i get the rainbow spiral cursor.
I have to use expose and switch to a new space, after which everything works perfectly.
And after a while, the frozen space goes back to normal.
Surprisingly, it doesnt freeze if i dim the brightness of the screen to zero (or put it to sleep)