no monobehavior script in file even after a new project is created eveytime the same error

I was seeing one of your tutorials and everything was working fine but all of sudden I don’t know what happened that now even after starting even a new project I m getting ’ no monobehavior error 'and now it became constant I can’t do anything even run the project I TRIED EVERY POSSIBLE way BUT I DONT KNOW WHAT’S WRONG WITH MY ENGINE OR CODE OR UNITY

Pls help

Have a look at this question. I think it might be about the same issue: