I am having similar problems with my 6600GT AGP card
As soon as i start a game like Quake 3 or Doom 3, the computer shuts down after the opening game screen or if i go to play a game
I have tried everything and cant understand what you mean about the power supply
There is no '4 pin adapter' that i can see
My card is an AGP & i am using Win XP
PLEASE help me!!