I have geforce 9400gt graphics card...the problem is whenever i start my PC there is a rack on the upper part of my monitor while windows xp is written....after that the screen is ok and also the driver is not installing...it shows error...i tried to install newer version of driver and tried my card in another fresh pc but it shows the same error...what to do.....?Pls someone help....

Unfortunately, one you didn't tell us anything about your computer (except OS and graphics), two you didn't tell us what error you are getting, and three what you are saying makes no sense. Please elaborate on what is going on.

Is this the video driver you tried installing?

http://www.nvidia.com/object/winxp-2...ql-driver.html

you may have the wrong driver, make sure its defiantly the correct driver from the Nvidia site.

Also wipe your old VGA drivers using a program like driver sweep in safemode.

I know the above driver works, I have the exact same nVidia card.

(That driver works for XP, Vista, and Windows 7.)