Before installing a new card you should always uninstall the prior driver then uninstall the old card from device manager then shut down an pull the card. You then install the card and boot and install the driver for your card. The link that taurea gave for that driver is correct however it is linked directly to that driver version. In the future if you want to look for drivers for your card this is the link to the AMD download page: https://www.amd.com/en/support
