Manually enabling a graphics card enables you to fully utilize its power. Regardless, you will almost always have to manually enable the graphics card on computers that don't support plug-and-play. It's a simple process consisting of just a few steps.
Login as an administrator to the PC and navigate to the Control Panel.
Click on "System", and then click on the "Device Manager" link.
Search the list of hardware for the name of your graphics card.
Right-click on the hardware and select "Enable". Exit and save changes if prompted.
Make sure the on-board graphics unit is disabled when enabling a freshly installed graphics card.