Hi I Have alreadylost my mind.
The problem concern the way of work that the 9800Gx2 is making.
After instal all drivers at new OS i instaled the Crysis to check graphic card.
I couldnt belive what happened.
After click shortcut Crysis the screen made Black. After few sec PC Rebooted.
I've tried a lot of different drivers and situations occured over and over again.
the strannge point is that GPU test are workin, 3d mark also.