Hi, I have a Macbook Pro Mid 2012 running Sierra. I turned it on today, got the usual chime and startup screen, entered my password to log in and then the screen went black with just the cursor showing. I tried several restarts, reset PRAM and SMCand nothing changed. I stumbled on a thread which said to enter single user mode by powering up and holding command and s. Wait for the command prompt (root#) and type '/sbin/fsck -fy'. This suggested the disk was ok. Then type '/sbin/mount -uw /' and then type 'rm /Library/Preferences/com.apple.loginwindow.plist'. I did this the typed reboot and this appeared to work, after I entered the password this tim it booted to my home screen. Now however I can't load safari or the app store. I know that I'm connected to wifi as I can get emails and stream music through Spotify. When I click the safari icon the screen comes up but nothing loads. If I type anything in the menu bar there is just the cross on the right hand side and no blue loading bar, it just does nothing. I have compared the system preferences>network settings tab with another identical machine that is working without any problems. Anyone have any ideas what I can try?