from what i have found elsewhere it boiles down to your gfx card. the driver has not been able to restart after it failed. this could be caused by a hardware fault on the gfx card, whether it just be a heat issue or a voltage issue. if your gfx is overclocked remove it, if its a factory oc then drop it down to stock for that card and see if the problem persists.
if it is a failed driver you should see a refrence to it in the event logs. if there was enough time between the driver crash and the bsod.