Welcome to Justanswer.com, my name is ***** ***** I will do my best to assist you.
Im going to assume that you have been attempting to press the correct keys and type the correct commands and yet nothing is working for you.
Ive seen issues like this before, what you are having is a keyboard failure.. Either your command key or other keys simply arent working. Y ou are welcome to call Apple, and I assure you they will attempt to walk you through the same steps our experts above have attempted to walk you through, and surely that will end with the same result. At some point a tech either here or at apple is going to come to the conclusion I have..
That you need to try a new, USB mac keyboard.. Once you have that USb keyboard connected and working.. You will then be able to get into single user mode at which point, simply typing the commands will allow you to reset your password. Please understand that this isnt a suggestion or an assumption, Weve all worked on macs for many years and reset passwords exactly as we are suggesting many times.
So lets assume again that you have been pressing the correct keys.. You need to get a working USB mac keyboard.. Here is a low cost example
( Note, there is a vast difference in a windows keyboard and a mac keyboard, and the most important difference is the Apple / command key and the option key layout. You need those two keys and it must be a mac keyboard or else you cant enter single user mode, etc )
Now, once you have the new usb keyboard.. This is your first step
Shut down your Mac.
Locate the following keys on the keyboard: Command (⌘), Option, P, and R.
Turn on your Mac.
Press and hold the Command-Option-P-R keys immediately after you hear the startup sound.
Hold these keys until the computer restarts and you hear the startup sound for a second time.
Release the keys.
Once complete, shut down the mac and then start with Command S .. This will enter the single user mode, which is basically a blank screen where you can type commands.
Then, you will be able to type in the commands needed to reset the password. The key is, getting your keyboard to pass the correct boot key sequence to the mac. And after reading everything above, its clear that isnt happening. ( hence why you dont h ave a working password *****)
A new keyboard will solve this issue.
Senior Technician and Network Switching Systems Operator / Maintainer.