Updating the case.
Today (4.09.2016) the drivers failed me as well (I did not change anything in the settings - it occurred during watching a movie). Resolution went down to windows basic drivers resolution 1366 × 768 instead of my 1920x1080
and the icon in device manager shows that the dedicated card has a problem.
So I did not solve it, but here is what I did and what strange findings I made:
I uninstalled the hardware via device manager and installed latest drivers - when I read the supported hardware it shows both, my APU and my GPU as supported, but the installation software shows me that my hardware is not supported.
I have read that I should try the AMD Cleanup Utility - so that I did.
Nothing changed - AMD radeon settings are not opening.
The Drivers say my card is not supported.
And the device manager shows errors on my GPU:
Please help me...
I would really not like to reinstall the whole windows stuff