SDB:AMD graphics troubleshooting
fglrx is not supported in openSUSE Leap 42.2+. If you need to remove fglrx because of issues (e.g. X is unable to start) or prior to an upgrade, please follow these instructions to re-enable the open source radeon driver.
One of the first things fglrx does to ensure that radeon doesn't interfere with it is it blacklists the radeon module so that the kernel doesn't load it while booting.
When fglrx is installed, aticonfig creates xorg.conf containing configuration details for running fglrx. The default configuration files are in /etc/X11/xorg.conf.d/, so it's ok, in this case, to completely remove xorg.conf.
The next thing you'll want to do is to load the radeon module. Modprobe makes this easy:
Restarting X is relatively simple: Ctrl - Alt - Backspace + Backspace
Mesa is the open source implementation of OpenGL.
Updating Mesa may improve performance, especially on older versions of openSUSE.
Replace "42.3" with your version of openSUSE.