still can't update my nvidia 8400m g

hi,
i have Asus F9S
with Nvidia GeForce 8400M G 128mb
Windows 7 Ultimate 32bit

i have a problem with my graphics card, i can't update it to Nvidia driver, all what i can have is the standard VGA

i tried to download the driver and install it, but once i finished and restart i couldn't log in to the OS, i got blue screen with tall messages (white letters), i can read some error message but can't get it coz it's disappear very fast

i can get in with safe mode, and delete the driver to log in to the OS
or i have to restore the system to a point before the card updating

i have updated the BOIS too, but still have the same problem

i tried this too
NVIDIA Driver - Convert from Desktop to Mobile (Laptop)

and still can't update the driver

** this problem make me use an external monitor coz with the standard VGA all what i can see from my laptop screen is white, blue and green lines, i thought it's the screen and i changed it but still have the same problem with the new one, so i decide to use the external monitor until i found a solution

** i need to update the graphic card driver to can use some video and images editing program .. so it's very important for me to got the Nvidia driver

you mean the Nvidia folder? or just the .inf file ?
which one i should leave on desktop ?

i did what u said .. put the Nvidia folder on desktop and complete the steps
the OS log in then after few seconds the screen became v.strange .. many colors ..
then the windows stopped suddenly and i couldn't move the mouse
then i try to restart it .. but i couldn't get in to the OS ..
i make me made a restore to the system to be able to open it
and it get back to the standard VGA !!!

Do you have an oboard video and is it disabledi n your bios?

i couldn't understand this part !
u mean i have an external video connecting to my laptop?
if u mean that no i don't have an external video connecting to my laptop
i have an external monitor connecting to my laptop, coz i can't see anything in my laptop LCD except blue, green, white, and black lines.. so i need to connect the laptop to an external monitor to see what i'm doing .. the external monitor is connected to the laptop via VGA port.
this is a snap shot from the BIOS screen if it will help:

Would you please take a snip of your device manager and post it with the display adapter expanded

this is a snap shot to me device manager .. it's in arabic ^_^ .. but i marked the display adapter.. it's with the VGA standard

You could also try using a modded driver from NVIDIA & Laptop News | Latest NVIDIA drivers and related news | laptopvideo2go.com

i saw the link u provided me .. i found the same driver i have download :
NVIDIA DRIVERS 260.99 WHQL

or should i look for another driver?
mine is ( Nvidia GeForce 8400M G)