happens to me too but i have never fixed it or found a way to fix it. i have thi problem on 2 mobos aswell, MSI Neo PLat. and DFI 745 UT board. I ahve checked everything but it still deosnt make a difference.
i played till like lvl 56 , there are 200 levels plus 10 shadow level with the expansion. It was fun and i could see some people really liking it but then i bought WoW and never looked back. Its very fun and free so its worth a shot.