Coprocessor error code 28  

After installing the new drivers from Nvidia (195.62, 197.16 and then 258.19) I still have the drivers for this device and are not installed (code 28) error. I have tried to uninstall the driver and re-boot the machine and windows finds the hardware and I get the same error.

When I updated the driver, I download the driver file, go into the extracted directory and run the setup.exe file. Then I go to the device manager and update the driver for this device and specify the directory for it to search on my hard drive.

I have a GeForce 8400M GS video card and am running Windows 7 Ultimate 64-bit. My laptop is an HP dv9500z (Product GP347AV). I am running an AMD Turion 64 X2 2.2 GHz processor.

Can anyone help?

Have a look here:
Latest NVIDIA ForceWare Video Drivers Windows 7

I downloaded the most up to date driver (257.21 64-bit) and uninstalled the coprocessor device in the device manager. When I re-booted my machine after driver installation, Windows saw the new hardware and tried to install a driver for it. But, I am still getting the Windows error "Windows cannot find the device software for your device". When I pick from a list and select the NVIDIA GeForce 8400M GS dated 6/17/2010, Windows finds the driver but says "the driver selected does not support this version of windows". And I know I downloaded the 64-bit Windows 7 version of this because there is a sub-directory under 257.21 called WinVista_Win7_64.

I solved my own problem by installing a newer version of the AMD chipset drivers from HP (sp37730) and rebooted.