This actually happened quite a few times before when I was trying to play Heroes of Newerth. To fix it I just lowered the settings on the game.
I wanted to play another MMO, but I had the same problem when I first tried to play HoN, so I decided to upgrade my graphics card. thinking it would fix the problem.
It just made it worse.
Now, I can't even play Maplestory, because my computer will just reboot itself.
I attached my dxdiag.
I don't know much about computers, so I need a lot of halp here ;;