Windows 10: How do I fix my pc from having a black screen and a cursor

My pc was fine and everything worked minus my games I tried to play having 5 fps like on fortnite even tho I have a 4090, and I had saw a watermark saying I needed a product key so I plugged the one that I had into it and now my pc is staying at a black screen with a cursor that has a blue ring around it. I have tried to do all the combinations of keys but nothing works. And I have tried researching for it but the only thing I get are about windows + shift + b and that doesn't work. And I just built the pc a week ago so nothing is outdated. I'm not sure what I need to do

:)

 

Black screen with cursor.


Hi, I am prajwal , my PC is facing a problem.when I installed drivers in my PC, after that screen had become black with cursor , I could not able to do anything, I can't see task manager too.So I want to format my PC.But I want to back up all my stuffs.What and how I should do plz suggest me.
Thank u in advance.

 

how to fix black screen with cursor when start my pc

how to fix black screen with cursor when start my pc