Windows 7 graphic card problem

[Romero Pablo Aguillar]

I bought and installed a Nvidia GeForce 8400GS but windows (7 64 bits) does not recognize it. Control Panel shows nothing, no graphic adapter in despite of the images show ok in my monitor. In Windows XP and Ubuntu I experience no problem. Does anyone has some kind of experience with an issue like this? I've been trying to solve this problem for 4 days. I do not beleive that is a BIOS issue and definetly is not hardware, because with XP and Ubuntu I have no problems. I will be greatful if someone help me.
PS: sorry my bad english.

 

[kemical]

Have you installed the GPU driver?

 

[Pauli]

Windows 7 updates?