Exactly what software are you trying to install?( the actual name)Since you have a dedicated graphics card, the only drivers you will need to install are the chipset driver, lan driver, and audio driver.
Fall 2006 Original NVIDIA Chipset Drivers Fall 2006 Original NVIDIA LAN Drivers Fall 2006 Original Realtek High Definition Audio Drivers
They should install directly. Finally, are you using a recovery disk or an OS disk?