I hate psu problems. I especially choose a 800 watt high end psu that was better than average 3 years ago and it blew up 3 days ago. atikmdag.sys was causing bluescreens once every day for a few months and I never suspected the psu. This time I decided to get the best psu ever produced and got myself a Seasonic Platinum 860watt psu and it's running great and that error is gone too.
So my advice is to pay special attention to the psu you are using with your computer.