I have this pavilion notebook with windows 10 and the 8400M / R3 in it. Standard notebook from HP except running windows 10 however it has been running windows 10 for a long time without problem. Just a couple of days ago I find that the PC is hanging at boot and after playing around it seems that there was an updated driver for the radeon card within windows 10 anniversary edition. Now I'm stuck in that the system hangs during boot (blank screen) whenever I have the radeon card running but if I disable the card in drvmgr I can get the notebook to boot and run OK. Trying to wind back the driver doesn't work because windows 10 just wants to install it again but I found a way around that. I can go back to the old driver from HP support site but then something else is updating the driver anyway - I suspect AMD driver loader.
Anyone else having trouble with the 8400M and windows 10 anniversary?