boot – Black screen both at normal and safe mode on windows 8.1

After my system finished scanning and repairing I got a black screen with no cursor and keyboard commands were not working. I tried many solutions on the internet but all didn’t work. I tried a solution that requires me to get into safe mode and uninstall some devices but when I try to log to safe mode,I see the same black screen . Please any idea on how to fix this black screen of death without losing my files?