You can get driver sweeper here (http://phyxion.net/item/driver-sweeper-320.html).
Install it and run it to get rid of the remaining driver elements. Windows comes with native AMD drivers as part of it's system files. This is why you can run the vid. card. right after installing the OS. They are never the most current. You may be seeing these drivers. Please explain what "it still seemed that some drivers were not uninstalled" refers to? Are you going to use an AMD or Nvid. card?