Object reference not set to an instance of an object

Hello, when I opened the project tools window for the first time, it worked fine. In my case, I accidently (idk how) put 111111 in the Quick Start's client field. Unity crashed and I tried to get it working. I could not find any file that contains the data of the project tools. I deleted the project and downloaded it again, in hope of the save file got deleted. I opened the new project and the same thing happened. I reinstalled Unity and it still crashes when opening project tools (I really don't want to format my hard drive).

Does someone know where this is saved or how I can reset project tools?
I appreciate any help I can get.

~ Yolo

 

If I remember correctly you can open them from the menu...

 

I fixed it, but I still need help with this:


Everything is just black; probably the cam is not working, and I really don't know this one.



I tried to host a game, and this happens:


Can you help me, @karstenv ?

 

Seems like some object is missing, and causing all that... idk what to do