I have it on system with and without sp2. Just discovered another thing. Here’s what I did:

Choosed Avast as screensaver.
Clicked on example.
Screen saver worked.
Stopped the screensaver by moving the mouse.
Then click cancel in the screen settings.
Everything looked normal.
But the Avast screensaver was still running in taskmanager !
Even when I selected no screensaver and clicked ok, it kept running.