Follow these steps:
1. The first step in disabling your onboard graphics card is to boot up into Safe Mode (Hitting the F8 key during system boot up and selecting the option that just says Safe Mode) <– Be patient, this boot up may take longer then you are use to
2. Right click the My Computer Icon and choose the Properties option
3. Navigate to the Advanced tab and look for the Device Manager option
4. Look for Display Adapters and click the ‘+’ option to expand the properties
5. You should find something that may say “Intel Integrated Graphics” or something that says Onboard or Integrated with either your motherboard manufacturer’s name on it. Right click that name and select the properties option
6. Select the Disable tab (do NOT uninstall)
7. Shut down your computer after it has been disabled
8. Once your computer is completely shut down, remove the power cable and all other cables from the back of your case and open up the case (Make sure you properly know how to work inside of a computer case to risk shocking or damaging existing parts)
9. Install your new card and close case/reattach cables
10. Boot up normally. Your screen will be enlarged as the card is running in a lower resolution but once you log in, you will be able to install the drivers that either will be found automatically or will be prompted for if you have the CD or disk that contains them