issues restarting Windows 8. HELP

So I had too many pages open in my computer. I do this often but sometimes it gets to the point where it freezes and I have to reboot. So that is exactly what I did. However this time when I did it all I got was a black screen. Since I have very little actually on my computer anyways I just hit reset. I figured things would be just as easy the second time around but its not. Before it said I could not install windows defender and when I deleted Norton it let me install windows Defender. However now the only thing on it that will work is "Microsoft security". I went into Microsoft security and put it to Off mode but it still wont let me add WindowsDeffender. I am currently in Administration mode. As well at this it wont let me go back to edit the setting of my user either. I fear maybe I erased something I wont be able to get back anymore but I don't know how to repair it now. Could someone please help me?