I had gone with Windows Vista upgrade for Sony Vaio VGN-FZ11Z laptop. I had upgraded to Windows Vista Ultimate. It came with Windows Vista Home Premium. After upgrade I am getting issue while playing games. It has a NVIDIA GeForce 8400M GT graphics card. It went black at the time of playing game. I restarted tge system but still the issue is same. Sometime there is a black screen and dotted vertical lines. The system freeze at that point. I had gone with restore also also still it is not working. This is a driver issue. How to fix the same.