Hy,
i had the same problems with my HD4870
but thanks to the guru3d Forum and dellon132 I managed to get it running with a driver renamer.
http://forums.guru3d.com/showpost.php?p=4487884&postcount=1
bevore that I tryed a lot from inf data renaming, manually installing all drivers, win7 drivers... that was the thing that worked.
I hope I could help you.
See you on the battlefield
