Black screen after log in - No safe mode

[JanetC]

Ok so my Toshiba laptop was updated to windows 8.1 and everything was working fine but now when I turn it on it logs in then the screen just turns black. I don't know much about computers so I did some googling and tried to open safe mode using shift+f8 but nothing happens. What do I do???

 

[Greenpernod]

just f8 tapping when booting to get to advanced start menu for safe mode.