If you allowed Windows Update to automatically update device drivers then that would explain why you have a black screen. Windows Update, in some cases, will download and install a screwed up device driver for your graphics card.
Safe Mode uses a basic Microsoft graphics driver.
You can download and run DDU (Display Driver Uninstaller) to remove the current driver:
http://www.guru3d.com/files-details/display-driver-uninstaller-download.html
You can then download the latest graphics card driver from AMD and install it.
http://support.amd.com/en-us/download