Gii #404 won't start. What to do?

Question

Yii

Hello! To begin with, I want to say that I tried to solve this problem myself! Climbed the entire Internet! Tried all options. But I still can't launch gii.
Even reinstalling yii2 did not help. It sounds strange, but I even reinstalled Windows. The error does not go away. I'm desperate. Help me please! So I'm new to the php language learning environment and this framework.