What you do, is you install the graphic card, and when you get in, disable the onboard in control panel > system > hardware > device manager > find your onboard > right click > click properties > and disable. After this, it will prompt for a restart. So after you restart, go to the Nvidia or AMD website. Which ever is your new card, and download the latest driver. Or you could disable first and install the graphic card, and then download latest drivers.