if I am playing a game, and exit the game and play a video, one of my monitors just goes to graphical errors/glitches/lines.... if i play a flash video after i play a game... i found this thread on it. 
  
http://www.overclock.net/t/1037034/how-to-fix-dual-monitor-screen-flicker-ati-amd-guide 
  
  
I havent had a chance to disable hardware acceleration in flash videos yet to test that out, but damn that shouldnt happen anyways. 
  
i think I am going to try this also when i get home if the disabling hardware acceleration in flash does nothing 
  
http://www.overclock.net/t/988215/how-to-remove-your-amd-ati-gpu-drivers