Easy.
1. Uninstall Existing drivers
2. Use DriverSweeper to remove all remnants of drivers
http://www.guru3d.com/category/driversweeper/
3. Install new graphics card
4. Install new drivers.
1. Uninstall Existing drivers
2. Use DriverSweeper to remove all remnants of drivers
http://www.guru3d.com/category/driversweeper/
3. Install new graphics card
4. Install new drivers.