The PC in question is running IE 9.0.8112.16421
Windows 7 64 bit
I have installed (and reinstalled) the latest flash player 11.2.202.235 to no avail.
I have disabled hardware acceleration
I have installed the latest graphics card drivers from the manufacturer.
When I attempt to play a video on sites like youtube, the player shows the initial frame, but then shows only the background (as if the player weren't there at all) and plays the audio only. If I move the screen up and down (using the scroll wheel) repeatedly, the player refreshes and will show a frame of the video then it goes back to the background color.
I've tested in both Firefox and Chrome and the player seems to work just fine in those browsers, so it's some sort of conflict with flash 11.2 and ie9
Currently, I have three machines that are experiencing this problem, but that number seems to be increasing. It was only two last week.