Have you completely removed your last card's driver ?
1_Download and install Driver sweeper from here:http://www.guru3d.com/category/driversweeper/
2_Uninstall your current driver from add/remove programs and restart
3_Boot to safe mode and open driver sweeper and click on "ATI" and then click on Clean
4_Reboot normally to windows and install the driver again,(You may want to install Catalyst 9.12 since its newer),after the installation restart and its done.
Check if it helps