Did you try the 64-bit drivers provided by HP and/or the 64-bit drivers provided by AMD and you still received the error?
If so, you may need to download and install Driver Fusion (replaced Driver Sweeper). Boot into safe mode and run Driver Fusion to remove any existing Radeon drivers). Upon completion, reboot the system and attempt to load the 64-bit drivers again.
Get Driver Fusion here:http://treexy.com/