Your question is Troubleshooting No Boot Issues. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Describe how you would troubleshoot a customer device that has no power, no boot, no display, and no post, including how you would use adapters, check the keypad, and isolate the root cause.