I am having the same problem. I recently started playing guild wars 2 jus this week and I realize OP is relatively old now but I am having the same issue as the game will start to flash to black screen and back to the game screen then freeze displaying the last point i was at in the game, at which point I cannot ctrl alt delete alt tab or do anything on my computer. The peripherals completely freeze and my computer becomes unresponsive short o0f sound, i can still here game sound,skype,etkittenil i begrudgingly restart my computer.