Black login screen

Hello everybody,

I just had a problem with shutting down my windows 8.1 pc, it didn't wanna shut down at all and yeah i just shut it down using the button of the power supply.
But now i'm having a problem with one of my users on the computer it's having a black screen like said in the title :/.
It's my only admin account on the pc.
And i was able to login to the other non-admin account once but actually failed and wanted to change to the admin account and yeah i got a black screen :/
BTW: I can see my mouse sometimes for a little while and then i goes to the middle and dissapears until i move the mouse again... , i can also see internet icon and language settings icon flickering.
I also don't know how to get to my boot menu.

So anybody got any advice?


Regards Jekeke123,