I was on youtube earlier on watching a clip on HD. I tried fast forward, however, the video looked like this for about 3 seconds before turning normal again.
Is this a typical problem with Flash or is the GPU dying?
It looks as though it is only happening inside the flash window so that would lead itself to be a flash problem rather than a GPU problem. A GPU problem would much more likely have something like that happen to the entire display.
He's right, its not a GPU problem or the whole screen would be misbehaving, i would advise updating flash and if that doesnt work reversing to an older version like 9.0.