nVidia GeForce 8400M GS graphic problem on VAIO VGN-SZ680n

Hello guys

I have some kind of graphic problem here. you may see in the photos.
I removed original OS (Vista) and installed windows 7 and after a while, when I was doing some photoshop stuff things changed.

As it show in photos, I have some knid of periodic vertical hashed blue lines over my screen. that starts to show when computer powers on.

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Notebook Model : VAIO VGN-SZ680N
Original OS : Vista Business x86
Graphic Card : nVidia GeForce 8400M GS

Please let me know if I should provide any additional information.

Thanks in advance

 

Have you tried hooking the laptop up to an external monitor? If the problem carries over to the external monitor it could be something with the video card or software. If it doesnt carry over, then its something to do with your lcd screen most likely.

 

Yes, the problem still exists with e graphic card attached to a monitor. and thats right. but I think thats a driver problem because it originated since I change my windows from original Vista (OEM) to Windows 7. everything was fine and after a while using win 7 It crashed (while I was working on photoshop CS4) and after that it was as it is now.
but I restarted many many times and I dont know why it turned to be ok.
Display was working fine. but after 2-3 days It changed back to this mode and still exists so.

I downloaded the right driver from nVidia for Windows 7 32bit but it says does not detect the right graphic card on the system and does not let me to continue installation of new driver.

In device manager I still have the default VGA Driver