This is now happening with 11.8.800.94 with browsers and Weather Channel Desktop app. White, black or blank screen on many web pages -- but not all. YouTube seems unaffected. When right click on a blank/black/white screen, grayed out message "Movie not loading" appears.
Uninstalled Flash Player using adobe uninstaller, then installed older verisons dating back to 11.2.x. NO CHANGE.
Obviously I have no idea what is going on, or what to do next.