my nano can't boot up??

i have tried many times ,and i do it follewed by https://github.com/NVIDIA-AI-IOT/jetbot/wiki/software-setup & https://developer.nvidia.com/embedded/learn/get-started-jetson-nano-devkit, but my nano can’t boot up, the display screen doesn’t work. why? i use nano usually two weeks ago, everything is ok that time.

i hope someone may help me to solve the problem.

I cannot help you if you don’t share any log.

Please enable serial console and share the log. Thanks.
https://www.jetsonhacks.com/2019/04/19/jetson-nano-serial-console/

thanks a lot, i will do it as followed.