I've recently run into an issue with my new setup where whenever a YouTube video begins to play (even through an ad on a webpage) my computer locks up. 

(Details: First the screen separates from the mouse, making it so I am unable to click anywhere.  Then, about 10 seconds later the mouse disappears.  Finally, about a minute later my music cuts out, and I have to reset my PC.  Even right in the beginning, Ctrl+Alt+Delete or any other keyboard commands have no effect.  Also, the YouTube video does not actually play.)

My setup:
Running dual non-reference 6950's at 910MHz Core, 650MHz Mem, 1149mV, 79 degrees each under 98% load.
Windows 7 64-bit, running the Catalyist 11.1 drivers (11.2+ drivers cause screen tearing when I attempt to boot into windows).
GUIMiner client, 2 OpenCL workers pointed towards BTC guild.
Flags for both workers, -f128.

Any advice or suggestions?  Bounty will be paid to anyone who can solve this problem, the amount will depend upon the ease of the solution.