Just uninstall the the ATI/AMD drivers. Then shut the system down, install the new GPU, and start the system. Install the 9600GT drivers from nvidia.com.
The ATI/AMD 4200 is an integrated video adapter built into your motherboard. It will be disables by the BIOS when you install the 9600GT.
I hope I'm typing this in the right box (nubie.. wat u expect ?
Thank u much for the prompt reply .
"It will be disables by the BIOS when you install the 9600GT." .... so , just uninstall from control panel > programs , and BIOS will take care of the rest ... Am I asuming correct ?