A black screen (in SuSE) is an indication of XF86Config containing incorrect information about your screen. If you can not boot to Runlevel 3 (text only) use LiveCD and mount the hard disk read/write. Change to /etc/X11 directory and look around for XF86Config* You should see a file with .original hanging around. Make a backup copy the file with .conf extension, and then copy the .original over the .conf file.

Another way is to boot to safe mode, and then configuring the screen.