I've tried -3- different times, did a full uninstall of 14.12 drivers first. The 15.7 driver package installed normally enough, it runs and appears to go through all the motions, but when complete it says there were errors and to view the log for details.
When I viewed the log, all of the drivers except the graphics driver were successful, but the video driver 15.7 was marked as "Failed." There was no error code or anything, so no clues where to proceed from here. I had to uninstall the 15.7 drivers that did work (just to make sure they didn't conflict) and reinstall the 14.12 drivers. Everything is working as before, but I would really like to try out these new drivers.