I had a new optional update show up in Windows Update dated September of
this year.

"ATI Technologies Inc. - Video - RADEON 9600 SERIES
Installation date: ?12/?29/?2007 5:17 AM
Installation status: Successful
Update type: Optional
ATI Technologies Inc. Video software update released in June, 2007
More information:
http://winqual.microsoft.com/support/?driverid=20064802
Help and Support:
http://support.microsoft.com/select/?target=hub"

This update caused DreamScene to have a black background and no video.
This update seems to be the same one that was dated August of this year that
I installed and the same problem occurred.
I installed the latest drivers after installing that update the first time
and my DreamScene was back to normal.
This time I used a restore point to get back to normal.

Seems to me that this update shouldn't become available to download an
install if it is causing system instabilities A novice might not know what
is causing his system to crash and possibly corrupting it so badly that he
can't even restore his computer, which is what happened to me a couple of
weeks ago when I installed that update.
I didn't know what had caused my problems at that time, as I couldn't
investigate the problem as I had to reinstall Vista from scratch.