Chosen Solution
I am trying to connect my new mac by HDMI to my unresponsive MacBook Pro mide 2015 which I cant use the track pad
First you can’t use a HDMI connection between your two Mac’s. You can use Target Disk mode to gain access to the second system if you can get it to respond. From what it sounds like you need a different option here. Are you able to get any reaction from your system? See if you can get into diagnostics using the D startup key. References: Understanding the Applications for Target Disk ModeMac startup key combinations
