I hav sony vaio vgn-fz11z laptop with Windows Vista Ultimate 32bit and NVIDIA GeForce 8400M GT graphics card. It went black while playing a game. I restarted but it showed black screen with dotted vertical lines and freezed. I restore it in safe mood. It did not show GeForce 8400M GT graphic card but just Standard VGA Graphics Adopter instead. I tried to reinstall drivers (sony vaio orignal) but on restart,it again freezed.

Then i reinstalled fresh vista 32bit. But its just showing standard VGA adopter card. when I Tried to update it with the driver for NVIDIA GeForce 8400M GT graphics card. it refuses saying that driver is up to date. Then i just run the setup file for the driver, it got installed and also shed in device manager as GeForce 8400M GT, but on restart it again hung with black screen with vertical dotted lines. Now i rolled it back to standard adopter VGA card and system boots. System also show vertical white bands as in figure while running or adopter card as shown below.

KINDLY HELP, IM CONFUSED WT TO DO

dear
i donwnload and tried it already.
if you run the setup it installs and shows nividia geforce 8400 in device manager too. but as soon as i restarts, again computer freezes with black screen with doted lines, Then i have to restore it back to VGA restore point and it runs.

i also tried to install driver via update driver option but it says
windows has found the driver but there is a problem, its handle is invalid ((

You might need a new graphics card

can it get repaired. I mean how can card be replaced and what will be its costs ??

which card will be better if i replace it. the system is

core 2duo T 7300
2 GB Memory
200GB HDD
Blu Ray