I'm running XP, so there is no UAC to disable...Run Quicktime Player from your Start/All programs.
Doesn't it blank your screen and turn off Aeroglass until you stop it again ?
It does on my system.
Have you disabled UAC ?
I just ran Quick Time from Start/All Programs with my Opera browser open to my home page on my site, but the screen didn't black out like yours did. I don't use Aeroglass.
Ok, try it now. I removed one widget (because it was giving me a "Security Warning" message, and saying that it was stolen code being exploited by someone, and to get the original widget from someplace else...which, when I went there, still showed the same message on the widget) from the home page.